Red Bull drivers Mark Webber and Sebastian Vettel said they were not concerned by the much-improved pace of the updated McLaren car in Friday’s opening practice for the German Grand Prix.

On a day of mixed conditions that included heavy rain during the afternoon’s second session, Britons Jenson Button and Lewis Hamilton produced the fastest laps when they topped the first free practice session.

Their runs in McLaren’s heavily revised car made the most of the only dry conditions of the day.

Defending double world champion German Vettel, who is seeking his first win on home soil this weekend, was 12th fastest in the dry session and conceded that Red Bull could not match the McLarens’ pace in the session.

But, he told reporters, that did not mean there was any reason to worry.

Vettel said: “They looked very competitive this morning, no doubt. We couldn’t go that pace, but we were not entirely happy this morning.

“It’s a Friday and it’s difficult to draw conclusions. McLaren looked competitive at Silverstone on the Friday as well and then their weekend was not so good. We have to wait and see tomorrow (Saturday).”

Webber, who added victory at Silverstone to his win at Monaco earlier this season, added that the changeable conditions made Friday’s running very hard to judge.

The Australian was 20th in the dry morning session.

“We can’t control the weather and it’s tricky for everyone to work out where to put your energy and set-up time,” he said.

“When the track is moving around this much, every lap basically, the lap-times are all over the place and people are very inconsistent with their times.

“In the end, we did a lot of laps and got everything we could have done out of those sessions.”

Button and Hamilton topped the times in Friday’s opening session run in dry conditions before Venezuelan Pastor Maldonado of Williams clocked the best lap time in the wet in the afternoon.