(CNN) -- Lewis Hamilton defied the conditions to record the fastest lap on the final day of Formula One testing at Barcelona Friday -- but the Briton refused to entertain any title talk.
Hamilton, who quit McLaren to join Mercedes at the end of last season, beat former teammate Jenson Button into second place with Torro Rosso's Jean-Eric Vergne in third.
Hamilton clocked a time of 1 minute 23.282 seconds, despite the constant rain and adverse weather at the Spanish circuit.
But the 2008 world champion insists his team is not ready to compete with the likes of Red Bull's triple world champion Sebastian Vettel and Ferrari's Fernando Alonso when the new season starts in Melbourne on March 17.
"I think people are talking us up at the moment," Hamilton told reporters.
"Vettel, and maybe Fernando, were saying I'm maybe going to be competing for the world championship, but I really don't see that happening at the moment.
"Of course that's our goal, but you have to remember the car was over a second off, sometimes two seconds off, last year and we've not caught up a second.
"Other teams will also have put a second on over the winter, so we've not gained three seconds, that's a fact.
"Hopefully by the end of the year, that's our goal, but definitely not at the beginning."
Elsewhere, McLaren's Button recorded the day's second fastest time, coming home in 1 minute 23.633 seconds with Vergne recording a time of 1 minute 24.071 seconds.
The best time of the week belonged to Hamilton's replacement at McLaren, Mexico's Sergio Perez, who completed his fastest lap in 1 minute 21.848 seconds.