Britain's world champion Jenson Button on Saturday clocked the fastest time of any driver during pre-season tests held at Jerez over the past two weeks at Jerez in southern Spain.
The McLaren driver, who will drive alongside 2008 champion Lewis Hamilton in the 2010 season which gets underway in Bahrain on March 14, recorded a time of one minute 18.871sec on the final day of the third winter Formula One test.
Spain's double world champion Fernando Alonso was sixth fastest on Saturday with a time of one minute 20.436sec in his Ferrari.
"If I was in another team I would look at Ferrari because everything is going really well and for now we have no reason to be pessimistic. As of today, it is the best car I have ever had," he said.
Alonso clocked the fastest time of the opening winter test in Valencia for Ferrari, while Hamilton, the 2008 champion, recorded the fastest time at last week's four-day test in Jerez.
"I think the Ferrari is a very strong car. I think they have better consistency than anyone at the moment," Button said on Friday.
"I think our pace is good but there are still areas we need to work on for me to be happy with the car."
A fourth and final pre-season test will be held in Barcelona next week before the season-opening race in Bahrain.
Formula One practice testing times in Jerez on Saturday:
1. Jenson Button (GBR/McLaren) 1min 18.871sec (108 laps)
2. Robert Kubica (POL/Renault) 1min 19.114sec (117)
3. Kamui Kobayashi (JPN/Sauber-BMW) 1min 19.188sec (117)
4. Vitantonio Liuzzi (ITA/Force India) 1min 19.650sec (80)
5. Nico Rosberg (GER/Mercedes) 1min 20.061sec (130)
6. Fernando Alonso (ESP/Ferrari) 1min 20.436sec (137)
7. Jaime Alguersuari (ESP/Toro Rosso) 1min 21.053sec (139)
8. Mark Webber (AUS/Red Bull) 1min 21.194sec (87)
9. Nico Hülkenberg (GER/Williams) 1min 21.919sec (137)
10. Timo Glock (GER/Virgin) 1min 22.433sec (28)
11. Jarno Trulli (ITA/Lotus) 1min 23.470sec (141)