There are a number of ‘old rules’ in motorsport, but one of the most-quoted is: "The first person you have to beat is your teammate."

Formula 1 has seen a number of tense teammate moments in 2018, the strongest example coming in Baku when Red Bull drivers Max Verstappen and Daniel Ricciardo collided. Force India teammates Sergio Perez and Esteban Ocon also touched in Singapore, while even the champion team, Mercedes, came under fire for swapping Lewis Hamilton and Valtteri Bottas in Russia.

But out of all the teams this year, who had the most balanced line-up and, therefore, the strongest “number two” driver?

To work it out, we’ve taken the lower-scoring driver from each of the 10 F1 teams this year and tallied what percentage of their teammate’s points they scored, giving us a final ranking of who the strongest 'number two drivers' were in F1 this year.

10. Brendon Hartley, Toro Rosso – 13.79 percent of teammate's points

Pierre Gasly: 29 points
Brendon Hartley: 4 points

It was a tough year for Brendon Hartley at Toro Rosso, capped off one day after the season ended when the team confirmed it would be replacing him with Alexander Albon for 2019.

Hartley certainly endured a lot of bad luck, such as in Canada when he made a good start before a big accident with Lance Stroll, but ultimately ended the year with just three top-10 finishes and a final total of just four points.

By comparison, teammate Pierre Gasly racked up 29 points, highlighted by a fourth-place finish in Bahrain. That result alone tripled Hartley’s score for the entire season.

It leaves Hartley as – statistically – the weakest teammate in F1 this year, scoring only 13.79 percent of Gasly’s points.

9. Sergey Sirotkin, Williams – 16.67 percent

Lance Stroll: 6 points
Sergey Sirotkin: 1 point

Sergey Sirotkin’s rookie season in F1 was a baptism of fire as he languished at the back of the field with Williams’ troublesome FW41 car, arguably the worst the team has ever produced.

Sirotkin never took the chequered flag in the top 10, scoring his sole point at Monza only after Haas driver Romain Grosjean had been disqualified. Teammate Lance Stroll only made the top 10 twice, finishing eighth in Baku and ninth at Monza, but it was enough to mean he scored six of Williams’ seven points for 2018.

Sirotkin is now without a seat for next year after Williams opted to partner Robert Kubica with Formula 2 champion George Russell.

8. Marcus Ericsson, Sauber – 23.07 percent

Charles Leclerc: 39 points
Marcus Ericsson: 9 point

Marcus Ericsson may feature low down on this list, yet this was without question his strongest season in F1 so far.

As Sauber made rapid progress through the year, Ericsson became more and more competitive within the midfield, scoring his best F1 qualifying result at the penultimate race in Brazil.

With a little more fortune in the closing stages of the year, Ericsson’s points total may have been higher than the nine he finished on. But Ferrari-bound teammate Charles Leclerc unquestionably stole the show at the Swiss team this year, ending the year in style with three straight P7 finishes.

It meant that come the final points tally, Ericsson had accrued less than a quarter of his teammate’s points in 2018.

7. Stoffel Vandoorne, McLaren – 24 percent

Fernando Alonso: 50 points
Stoffel Vandoorne: 12 points

General feeling has been the most imbalanced teammate partnership in F1 this year was at McLaren, where Fernando Alonso bowed out of the sport by outclassing Stoffel Vandoorne all year long.

Alonso completed a qualifying whitewash, beating Vandoorne on a Saturday at all 21 races this year, and racked up 50 of McLaren’s 62 points, lifting it to sixth in the final constructors’ standings.

Vandoorne certainly had a handful of standout drives, many of which came in the early part of the season when McLaren’s struggles seemed less severe. He scored points in three of the opening four races, yet then failed to return to the top 10 until Mexico.

The Belgian ended the year with only 12 points to his name, making it less than a quarter of Alonso’s tally.

6. Valtteri Bottas, Mercedes – 60.54 percent

Lewis Hamilton: 408 points
Valtteri Bottas: 247 points

We then have a big jump up in terms of relative percentages where things get less one-sided – although in Valtteri Bottas’ case, it’s hard to sugarcoat what a disappointing year this has been.

Bottas has been deeply unlucky in 2018. He would have won in China had it not been for the Safety Car coming out, and would have won in Baku had the race finished three laps earlier (or his tyre hadn’t let go). That could have kick-started a very different season.

Instead, Bottas ended the year winless and as the only driver in the ‘big three’ teams to do so. He deserved to break that drought, but instead ended the year wishing to “disappear” and forget a rough 2018.

His contribution was still crucial in helping secure Mercedes its fifth straight constructors’ championship, but as Lewis Hamilton swept to the drivers’ crown, Bottas only matched three of every five points his teammate picked up.

5. Romain Grosjean, Haas – 66.07 percent

Kevin Magnussen: 56 points
Romain Grosjean: 37 points

As Kevin Magnussen stormed to his best year in F1 so far, teammate Romain Grosjean often struggled to match his teammate’s form, most notably at the start of the year when he went on an eight-race streak without even scoring a point.

Grosjean’s form picked up from there, with his first foray into the points coming in Austria as he finished fourth, marking Haas’ best-ever result in F1.

However, as he and Magnussen remained evenly-matched through the remainder of the campaign, he was not able to cut the gap to the Dane, finishing with a little under two-thirds of his points.

While Haas may have been left revelling in its strongest F1 season to date after taking P5 in the constructors’ standings, there will inevitably be feelings the 29-point gap to Renault in fourth could have been made up.

4. Daniel Ricciardo, Red Bull – 68.27 percent

Max Verstappen: 249 points
Daniel Ricciardo: 170 points

Daniel Ricciardo was the unluckiest man in Formula 1 for much of 2018, suffering a litany of issues that limited him to just two podium appearances – both of them race wins – this year.

It meant teammate Max Verstappen was able to bounce back from a tough start to the year to seize the initiative in the intra-team fight at Red Bull, with his post-Monaco form being particularly strong – just as Ricciardo’s was taking a downward turn.

Ricciardo failed to score another podium after his Monaco win, suffering six retirements in the final 15 races. Verstappen, meanwhile, was able to rack up 10 podiums in the same period, including two race wins, causing the gulf between the two drivers to grow dramatically through the second half of the season.

It meant Ricciardo finished the year marooned in P6 in the drivers’ championship, 79 points back from his teammate.

3. Carlos Sainz Jr., Renault – 76.81 percent

Nico Hulkenberg: 69 points
Carlos Sainz Jr: 53 points

While Nico Hulkenberg may have been the man to lead Renault’s charge to the head of the midfield in F1 this year, teammate Carlos Sainz Jr. proved to be a strong ally as the pair were separated by just 16 points come the end of the season.

Sainz enjoyed a six-race run of points in the early part of the year before his form took a bit of a dip, but he finished strongly with a charge to seventh in Austin and, in arguably his best display for Renault, a superb run to sixth at the season finale in Abu Dhabi.

Sainz may have only scored just over three-quarters of Hulkenberg’s points this year, yet it was an impressive display against one of the highest-rated drivers in the midfield.

2. Kimi Raikkonen, Ferrari – 78.44 percent

Sebastian Vettel: 320 points
Kimi Raikkonen: 251 points

Kimi Raikkonen may have been replaced at Ferrari for 2019 by Charles Leclerc, yet the Finn signed off at Maranello with the strongest year of his second stint for the Scuderia.

Raikkonen matched teammate Sebastian Vettel’s podium tally, scoring 12 across the course of the year, and ended his five-year win drought with a superb victory at the United States Grand Prix in October.

In fact, it was thanks to Raikkonen that Ferrari was able to remain in contention for the constructors’ championship for so long. He outscored Mercedes counterpart Valtteri Bottas by four points despite having twice as many retirements, failing to reach the chequered flag on four occasions in 2018.

Raikkonen showed signs of the ‘old Kimi’ in 2018. He was more comfortable than he has seemed for a long time, and, while he could not defeat Vettel in the final points standings, he was a match for his teammate more often than not this year.

1. Esteban Ocon, Force India – 79.03 percent

Sergio Perez: 62 points
Esteban Ocon: 49 points

The rivalry between Esteban Ocon and Force India teammate Sergio Perez has been so close and intense over the last two years that it should come as little surprise the numbers are also evenly matched.

Force India’s slow start to the season saw Ocon only score a single point in the first five races, but he was able to pick up his form thereafter, taking sixth-place finishes in Monaco and Austria.

The margins with Perez were fine throughout the year, only for the Mexican to finish 13 points clear thanks to a late flurry of scores in seven of the final nine races and a point-less end to the year for Ocon in the last four rounds.

Ocon will sit out of F1 for 2019 before a planned return in 2020, having fallen victim of the silly season merry-go-round, but to have pushed Perez so close in their two years together – maybe a little too close at times for Force India’s liking – has done his standing in F1 plenty of good.