Luthi fastest 125 on Catalunya day one.

Swiss teenager Thomas Luthi was the quickest 125cc rider on the first day of official tests at the Catalunya circuit near Barcelona, Spain, on Tuesday.

The Honda youngster, preparing for his fourth season in the world championship, set a time of 1min 52.789secs to oust Aprilia rival Mattia Pasini from top spot after the Italian had dominated the time sheets for much of a cloudy but dry day.

"This is a track I really like and the conditions today were perfect for testing," commented L?thi, who enjoyed his best ever career finish at this circuit with second place after a last-lap battle for victory with eventual World Champion Dani Pedrosa in 2003.

"I had a small crash but it was nothing serious and I was able to get back on the bike and set my fastest time," he continued. "Last season was a bit of a disaster for me but I have worked hard over the winter to make sure I am in top physical shape. I had a plate removed from my collarbone two weeks ago and I feel great. Hopefully this can be a good season for myself and the team."

With bright sunshine emerging for the final hour of the test, the majority of riders lapped until the track closed at 6pm. It provided an entertaining end to the day's action, with riders from five different factories establishing their top six credentials for what promises to be another open and entertaining season.

Whilst Gabor Talmacsi is entering his first season as a factory rider with KTM, former World Champion Manuel Poggiali returns to the class with Gilera, the factory with which he won the title in 2001, and Pablo Nieto is back at Derbi, where he made his entrance to Grand Prix back in 1999.

Mattia Pasini and Marco Simoncelli, meanwhile, are two of Aprilia's main hopes for glory, with the former having being crowned Rookie of the Year last season whilst the latter clinched his first victory at Jerez.

The 125cc official test continues on Wednesday until 14.00h before making way for their 250cc counterparts. The premier-class MotoGP machines take to the track for three days of tests on Friday morning at 10.00h.