Red Bull Racing's Sebastian Vettel has conceded a lack of concentration was to blame for his off this morning in opening practice for the F1 2011 Japanese Grand Prix.

The German, who only needs to score a point this weekend to successfully retain his drivers' title, went off at the Degner curves, when he ran wide and then skated into the barriers. Luckily though, the damage was only minor and with it happening right at the end of FP1, he didn't miss out on much track time.

Indeed he still finished both sessions in third - his best lap a 1 minute 32.095 seconds, which was just 0.194 seconds off the ultimate pace.

"It wasn't a big mistake this morning, but in that moment I wasn't 100 percent awake and mistakes around here can be quite costly," Vettel said. "I went off and tried to slow the car down, but I hit the wall slightly. It wasn't a big impact, but it did some damage to the car, so it wasn't perfect.

"It did affect our run plan a little, but we had a solid afternoon. The circuit seems pretty tricky this year on these tyres - they make the cars seem more alive, so Sunday will be an interesting race. Taking130R with the DRS open isn't as easy as it used to be!"

Mark Webber meanwhile had no problems and was fifth in FP1 and fourth in FP2 - his quickest lap, 1m 32.147s, only fractionally slower than the sister RB7.

"It's good fun, it's a great track and you can really let the car go around here, so all of us enjoyed it," Webber added. "It's a challenging circuit; we know there are a couple of tricky corners that can catch us out and we're all pushing to the limit obviously.

"We got some good information today; we ran both tyre compounds and completed some long runs, so not a bad day.

"I don't think KERS will be a problem here, but it's possible that the DRS might catch a few people out."