Although the McLarens were quickest in the morning, both RB6s were able to speed up to the tune of a full second per lap when the final 90-minute practice session was held in the afternoon.Mercedes' Michael Schumacher came closest to the Red Bulls in that session at the cool Circuit de Catalunya, but still lagging Sebastian Vettel's pace by a whopping eight tenths."It does seems that maybe one team is to be very, very quick at the moment," said McLaren's Lewis Hamilton, fifth.His teammate Jenson Button agreed: "It's horrible to say it, but I think Red Bull are untouchable this weekend."Mark Webber, two tenths slower than Vettel in the afternoon but still much quicker than anyone else, told reporters he thinks McLaren "probably weren't showing everything today".But Ferrari's Fernando Alonso, who like Schumacher was right on the non-Red Bull pace on Friday, disagreed."Red Bull were very, very quick in second practice and it will be very difficult for all of us to arrive to those times," the Spaniard said.