Valentino Rossi returned to the top of the MotoGP timesheets for the first time since re-joining Yamaha by leading Friday practice for the Grand Prix of Catalunya.

Fourth quickest in the morning, Rossi leapt from eighth to first in the closing stages of a scorching afternoon session, displacing team-mate and home hero Jorge Lorenzo by 0.049s.

"I'm very happy about the result," said Rossi, speaking in the Yamaha hospitality. "Me and my team know it is just Friday, but we are so happy - to be in front is a great feeling.

"In recent races we improved my performance in practice. Already Mugello was good on Friday, but to be in first position here is another feeling, another taste.

"But for sure it is just Friday. We still need to improve and there are some parts of the racetrack where we can do better, especially section one and three. But I am very, very fast in section two and especially section four. I am so happy about this.

"It will be important to start the race in a good position, but especially make the right tyre choice and have a good setting to keep a good rhythm. It is difficult to decide [which rear tyre is better for the race]."

The Yamaha team-mates split tyre testing duties on Friday: Rossi spending much of the afternoon on the harder option, before setting his best lap on the softer rear.

"I did a lot of laps on the hard tyre this afternoon, then switched to the soft just at the end. Jorge did the opposite, did all the practice with the soft," Rossi explained.

"We did this first to get a lot of information on the hard tyre and second to practice for qualifying tomorrow," added Rossi, who has struggled with the new qualifying format and been left on the third row for all but one of the 2013 races.

Rossi has won more grands prix than any other rider at Montmelo, including premier-class wins in 2001, 2002, 2004, 2005, 2006 and 2009 - when he overtook Lorenzo at the very final turn.

"It is a great pleasure to ride here in Barcelona. The bike is ok and now we have to wait for tomorrow and try to go a bit faster," he said.

"The temperature is very high, but for sure we will have to go in the 1m 41s on Saturday."

Rossi's best Friday lap was a 1m 42.297s, which is already under Dani Pedrosa's race lap record from 2008. The pole record is a 1m 41.186s set in the same year by Casey Stoner, using a qualifying tyre.

The seven time MotoGP champion, who fell after tangling with Alvaro Bautista on the opening lap last time at Mugello, is currently sixth in the world championship with one podium.