Williams Formula 1 technical chief Paddy Lowe believes it is "unreasonable" to take the points difference between Lance Stroll and Felipe Massa as a fair reflection of their respective seasons after the Canadian youngster moved clear in the drivers' championship last weekend in Mexico.

Stroll, 18, charged to sixth place in Sunday's Mexican Grand Prix to leapfrog Massa in the F1 standings, picking up 40 points to the Brazilian's 36 so far this season.

Massa had been expected to lead Williams' charge in 2017 given his greater experience compared to Stroll, but Lowe feels the points alone do not paint an accurate picture of where the advantage has been at the team this season.

"I don’t think we should dwell too much on the points in fairness to Felipe. He has actually had some major points losses that were not caused by him," Lowe said.

"[In] Baku, a lot of people said it that day that I could have won the race, but in Felipe’s case it genuinely was the case that if the car had not broken then he would have won the race.

"[In Mexico] it was a first corner contact so more unlucky, but Felipe has had a number of things like that and Lance far less so. It would be unreasonable to say that points reflect the full picture."

After failing to score points in his first six F1 races, Stroll bounced back with a shock run to third in Baku, and has scored points in four of the seven races since the summer break, acting as proof of his progress to Lowe.

"It has been a season for Lance that has had good and bad moments and has been very tough in some periods, and certainly it has been much better in the second half," Lowe said.

"He has settled down, particularly after scoring his first points in Canada, and then getting the podium in Baku. He races very much better than he qualifies, and I think people look at qualifying as a reflection of a drivers’ speed, because it is just very clear and easy to work it out from that.

"That doesn’t reflect on Lance as perhaps it should as it is his weaker area. He races far better than he qualifies at the moment but then you see glimpses of brilliance on that side with what he did in Monza.

"So I think he can unlock far better qualifying performances in due course.

"He is aware of that and something we are paying attention to."