Vettel cool on Valencia pace

Sebastian Vettel said he would be taking nothing for granted despite topping the times in a closely contested opening day of practice for Sunday's European Grand Prix. Shortly after his Red Bull team finished bolting an array of upgrades to his car, the 24-year-old cruised to second in the overcast morning session despite setting his fastest times on worn tyres. The world champion then clocked his fastest time of the day an hour into the afternoon session shortly after debris of a Force India car was cleared from the track following Spaniard Pedro De La Rosa's crash at turn 14. Despite a flurry of efforts from rival drivers, the German's time of one minute 39.334 seconds stood strong until the end of the session. Fellow German Nico Hulkenberg of Williams came close -- he wound up a tenth of a second slower, followed by 13 other drivers who all came within a second of Vettel's time. In spite of this, Vettel, who is chasing his third successive win at the Valencia street circuit, said it was too early to tell how effective his car's new upgrades had been. He believes the brighter weather predicted for Sunday's race could play a big part in the proceedings. "We have some new bits, but lap times are not allowing us to have a fair conclusion yet," he said. "For us it was important to have a clean practice, a clean day today with no trouble and no problems. "I am quite happy with what we did. I think conditions might change quite a bit until Sunday - again it was surprisingly cool today. "Sunday will be quite a bit hotter which could make a difference, but now we collecting some good data and we'll see now whether we made a step or not." Japanese Kamui Kobayashi of Sauber wound up third fastest ahead of Mercedes's Michael Schumacher and Bruno Senna of Williams. Paul di Resta was sixth fastest in the other Force India car followed by double champion Fernando Alonso for Ferrari and Romain Grosjean of Lotus. Australian Mark Webber wound up ninth fastest despite finishing just half a second slower than team-mate Vettel. German Nico Rosberg was tenth quickest in the second Mercedes. Both McLaren drivers and compatriots Jenson Button and Lewis Hamilton could not find the pace to match the frontrunners and finished the session 12th and 14th respectively. Felipe Massa also appeared to struggle and wound up 15th fastest. Webber had mixed feelings about the performance of his car with the 35-year-old finishing the day ninth fastest and struggling on soft tyres. "You get one lap or two laps on the softer tyre so we didn't do a good job on the soft at all," said Webber. "So a frustrating finish to the session and plenty to get on with here tonight. The car's working well, but there are areas where we can improve. I was happier on the harder tyre, the balance on the soft tyres wasn't great today, but we'll work on that tonight. "The wind was playing a role today - but there will be less tomorrow. Regarding changes we've made to the car, we'll know on Sunday if they're working well for us. The circuit will get a bit quicker as we lay rubber down, and it will get a bit hotter as well, so let's see."