Jenson Button defied early reliability problems with the latest McLaren to post the fastest lap of the opening day of 2013 pre-season testing at the Jerez de la Frontera circuit.

The Briton, who moves into the lead role at McLaren following the departure of Lewis Hamilton, had hoped to make a strong start to the important development phase of the season, but was sidelined after just a couple of exploratory laps, before he had even managed to set a time.

The fault was later confirmed in a newly-designed fuel pump, but replacing the errant part took the best part of the day, confining Button to just a late afternoon assault on the timesheets. Although he completed just 37 laps - compared to the session-high of 89 - the Briton still managed to post a time nearly a second faster than anyone else, clocking a 1min 18.861secs benchmark for the remaining three days.

Button spent the first part of the day's programme running a lower-lip rake to complete some aero mapping work. The end of the day saw the team evaluate the effects of a series of mechanical set-up changes, using both compounds of Pirelli tyres. Both the aero mapping and the balance changes fell in line with the team's pre-test expectations, and Button set his fastest time of the day on the hard compound rubber.

Times, of course, are all relative during pre-season testing, with the teams hoping more for reliability and the chance to put all-important miles on their new creations. While Button was at least able to finish the day, two of his rivals came up short in that department, with Mercedes' Nico Rosberg being forced to park up after just eleven laps when an electrical fire uncovered a problem that was not rectifiable on the day. Marussia rookie Max Chilton was also forced into an early bath, after running out of road during the afternoon session and damaging the MR02 - only unveiled that morning - in the gravel trap. The Briton, however, insisted that the incident was not down to him, citing a failure in the rear suspension.

"This afternoon's problem aside, I'm really happy with the start we have made to our 2013 campaign," Chilton insisted, "With a new car, there is always the potential for something to crop up and cut short the programme but, for the morning period everything went according to plan, which is just the start we needed.

"I'm sure the team will get on top of the suspension issue very quickly so we can all pick up where we left off and start putting some more miles on what is obviously a very promising package."

Rosberg, too, was disappointed not to have got a full day's running under his belt before new team-mate Lewis Hamilton takes over behind the wheel of the W04 on Wednesday. The German completed just three runs before being stopped out on track, with unburnt fuel in the exhausts subsequently igniting to give the photographers a spectacular shot, but not causing any serious damage. Further investigation identified that the fault originated in a wiring loom, and Mercedes immediately set about making modifications for day two.

"At the start of winter testing, you often encounter small issues because the car you're running is a brand new design," Rosberg reflected, "We had an electrical problem this morning and, once we had found the root cause, chose to modify the parts to make sure it didn't happen again. Of course, at this time of year, all you want to do is spend time in the car and get a feeling for how it's working, but these hiccups are just part of the game. During the laps I completed this morning, I had a good feeling with the car and it felt solid."

While Rosberg had set the early pace, it was left to Mark Webber to lead the pursuit of Button at the head of the times. The Australian concentrated on tyres amongst other basic evaluations, but came through late on to pip Romain Grosjean for second spot.

"It was pretty good," he claimed, "As Adrian [Newey] said at the launch, there haven't been big changes to the regulations this year and the car is an evolution of the one we finished with last season, so there were no big surprises. I think most of the drivers will sit back tonight and think today's times were pretty competitive.

"It was actually like a Friday practice session in some regards. We started understanding the tyres and there were a lot of positives. There's a bit of housekeeping we have to get on top of but, other than that, it's been encouraging. The car feels similar to last year's, so the main difference is the tyres. With these tyres, you're always on your toes. Generally though, the car feels pretty good, so I'm happy."

Grosjean, like Rosberg and Paul di Resta before him, also enjoyed time at the top of the charts, but had to settle for third spot as the chequered flag brought the end to a solid day's work for the Lotus team. The Frenchman was the fastest man on track for much of the day, as the team completed 54 laps of systems checks, temperature monitoring, data correlation and early aero evaluation on the E21.

"The feeling is good [and the car] feels very similar to the E20 from behind the wheel, even if it does look different from the outside," he commented, "Once again, Enstone has produced a car that is quick from the very first lap. We spent a little bit more time than ideal in the garage today, but that's normal in testing. I'm happy we completed 54 laps, and even happier that all of them were quick. We now have a good idea of the new tyres and we'll have some challenges from them - the grip level is there but performance does fall away with graining. That said, Jerez is a very specific track in this regard. The speed came easy today and we didn't respond to the other cars going faster in the afternoon. We should go even better tomorrow."

di Resta was also encouraged by the initial performance of the new Force India, running in the lead quartet for much of the day.

"It was a positive first day and we managed to cover lots of laps - so that's the most important thing," the Scot confirmed, "I felt very comfortable all day and we managed to get through the programme as we focused on collecting aero data and understanding how well the car correlates with our simulation tools at the factory.

"We also started trying to learn as much about the tyres as possible so that we can carry that into tomorrow and optimise the set-up. The new compounds are quite different with the new construction and I've already felt a difference with the balance of the car in the low and high speed parts of the lap."

di Resta ended the day a tenth clear of Toro Rosso's Daniel Ricciardo, who enjoyed a largely trouble-free day at the wheel of the Italian car unveiled on the eve of testing []. After the usual installation laps, the team began tackling a programme which centred on checking all systems without looking at performance - although, inevitably, the engineers could not resist looking at the aero numbers for the new car!

"It's good to be back behind the wheel of an F1 car," Ricciardo commented, "It was a long day to complete 70 laps, however, the main thing is that the car was reliable, which is a positive aspect and we got through our work schedule for the day.

"You cannot look at car performance on the first day, when reliability and comfort are more important and, on that front, my seat and driving position were good. So this was a day of tasks that were relatively simple, but also important."

Felipe Massa hauled Italy's 'other' team into sixth spot by the end of the day, having been clocked 1.3secs off the pace. Although the gap was bigger than that by the chequered flag, it was largely due to Button's flying effort stretching the field from the front. The entire day was given over almost entirely to acquiring data relating to the behaviour of the new car which, after the disappointing start to 2012, Massa reported positively on. The Brazilian continues behind the wheel on Wednesday, while team-mate Fernando Alonso sends tweets from the gym.

Both Massa and Nico Hulkenberg continued to trail the hobbled Rosberg until late in the day, but passed the German in tandem before the end.

Like Rosberg, Pastor Maldonado did not improve on his morning time as the Williams team concentrated on systems and set-up ahead of next week's FW35 launch. Driving the only 2012-spec car in the field, Maldonado completed 84 laps, second only to di Resta.

"We had no problems today and the car felt very consistent so we were able to learn a lot, which will be useful for the FW35 development," the Venezuelan reported, "We planned to run the FW34 to enable us to have a reliable car to test the new tyres with and also try some different set-ups."

Between Maldonado and Chilton came Giedo van der Garde in the new Caterham. The Dutchman was only confirmed as part of the line-up on Friday and helped to unveil the CT03 in the pit-lane immediately before the track opened for action.

"It's obviously far too early to make any judgements on the performance levels we can expect from the 2013 package but, compared to the car I drove in Brazil, it feels like we've made some good progress over the winter," van der Garde noted, "Tomorrow will be more of the same for us - running through more procedures and a few set-up options across the range of tyres we have available here and hopefully getting as many laps in as possible."