Sebastian Vettel has played down talk that his Red Bull Racing team will be untouchable in this weekend's Spanish Grand Prix.
With the German and team-mate Mark Webber having comfortably led the way on the opening practice day in Barcelona, rival drivers fear that they will not be able to match the pace of the RB6 this time out.
However, Vettel is more cautious about the chances of his team - and in particular believes McLaren did not show its full hand when the track was at its quickest on Friday.
"The lap times on Friday were irrelevant," said Vettel, who has taken just one victory so far this season.
"It is good to be fast, but nothing more than that. The McLarens are very quick here, and we don't really know what they did in the afternoon. It didn't look like they were pushing too hard on the new sets of soft tyres, so I think in qualifying it will be a lot closer."
Vettel also praised the raft of updates that Red Bull Racing put on its car this weekend - with almost every area of the car getting a tweak.
"It does not look as significant as some other teams' changes, like the Mercedes GP has its new airbox inlet," he said. "I don't know if you have been looking and it is not that easy to see - however it is a bit of everything. It seems to work."