Britain’s Jack Clarke assumed total command of the opening session of winter testing at Portimão, making a bold early decision to switch to slicks which paid dividends as the circuit dried dramatically in the final few minutes.

F2’s first day of official winter testing had opened with a sudden downpour just before the track opened, which added to the effects of a heavy thunderstorm the previous evening and ensured every driver adopted a full wet set-up.

The track remained wet for almost the entire of the opening session, but a faint dry line began to emerge in the closing stages and Clarke was the first to make the decision to pit for slicks.

After a few laps generating heat in his tyres, the move paid off dramatically as he raced clear of the field – extending his advanatge relentlessly in the final five minutes as he set a succession of fastest laps to eventually finish more than three seconds clear of the rest of the field.

Antonio Felix da Costa followed Clarke’s example by switching to slicks in the final minutes, and while he wasn’t able to get them up to optimum temperature he nevertheless improved upon his previous best to end the morning second fastest.

As Clarke and Felix da Costa found huge gains by switching to slicks in the final minutes, several drivers were also able to find improvements despite remaining on wets – leading to an extremely wide range of times as many who had been running at the front for the opening two hours suddenly found themselves falling down the timesheets.

Germany’s Thiemo Storz was one such example, eventually finishing third fastest despite topping the timesheets at the one and two hour mark on what was a highly impressive debut performance in the Williams JPH1B F2 car. He was however the fastest runner on wet tyres.

Benjamin Lariche was another who dropped down the order, the Frenchman opting to come in with ten minutes remaining and falling from first to fourth as a consequence.

Behind him, Kevin Mirocha narrowly edged out 2010 championship runner-up Jolyon Palmer to seal fifth, although both drivers had enjoyed spells toward the top of the timesheets during the session.

Ramón Piñeiro also finished within one tenth of Mirocha’s ultimate best in seventh, edging out fellow FPA graduate Vincent Beltoise – who completed 39 laps, the most of any driver – by just over three tenths of a second.

Behind them Alex Brundle responded to an early crash which restricted his running by setting the ninth fastest time. The Briton had clipped the barriers at the inside of turn three in the treacherous early conditions, but was able to return to the circuit in the final minutes and duly set a succession of personal bests.

Brundle’s surge left fellow F3 competitor Max Snegirev in tenth, fractions ahead of Poland’s Natalia Kowalska and Bulgaria’s Plamen Kralev. André Negrão enjoyed a solid opening session, although he was another caught out by the circuit’s dramatic late improvement as he ended the session 13th fastest. 2009 European F3 Open Champion Bruno Mendez rounded out the runners, although the Spaniard was only able to complete 11 laps.

FIA Formula Two Championship – Portimão – Day One, Morning Session:

1. Jack Clarke, 1:40.561s
2. Antonio Felix da Costa, +3.567s
3. Thiemo Storz, +4.713s
4. Benjamin Lariche, +5.429s
5. Kevin Mirocha, +6.300s
6. Jolyon Palmer, +6.319s
7. Ramón Piñeiro, +6.371s
8. Vincent Beltoise, +6.708s
9. Alex Brundle, +7.355s
10. Max Snegirev, +7.787s
11. Natalia Kowalska, +7.820s
12. Plamen Kralev, +8.035s
13. André Negrão, +8.200s
14. Bruno Mendez, +14.746s