Felipe Massa pulled off the surprise of the week when he put his FW36 on top of the timesheets on the final day at Jerez.
Hours after speaking about his "happiness" with his new team, he had a very happy ending to his first test as a Williams driver.
Posting a 1:28.229 on a dry track, Massa beat former team-mate Fernando Alonso by nine-tenths of a second.
The early part of the day, though, belonged to Alonso in the wet.
With the rain coming down at the start of play, Nico Rosberg set the early pace in his Mercedes W05 before Alonso, having swapped to the intermediate Pirelli tyres, edged him with a 1:35.334.
His lap time meant Alonso was leading the way at lunch ahead of Rosberg and McLaren rookie Kevin Magnussen in what, surprisingly, was an uninteruptted morning without a single stoppage.
As the day wore on and the track dried the incidents began.
The first belonged to Sauber's Adrian Sutil who went off backwards at the final chicane and found his C33 stuck in the gravel.
Shortly after that Massa went quickest with a 1:28.229 putting an end to Alonso's brief battle with Force India test driver Daniel Juncadella for the top spot.
The duo were not able to even attempt a fight back as minutes later Magnussen brought out the reds when he spun his MP4-29 but managed to keep it on the asphalt.
However, he wasn't so lucky the next time around when, with just over 10 minutes left in the day, he again brought when he went off while Toro Rosso's Daniil Kvyat also stopped.
The two incidents meant no one was able to put in a late challenge against Massa.
Two drivers made their 2014 debuts on Friday with Kamui Kobayashi in action for Caterham and Daniil Kvyat for Toro Rosso but it was another day to forget for Red Bull with Daniel Ricciardo covering just seven laps.
01 Massa Williams 1:28.229 86 laps
02 Alonso Ferrari 1:29.145 +0.916 115 laps
03 Juncadella Force India 1:29.457 +1.228 81 laps
04 Magnussen McLaren 1:30.806 +2.577 110 laps
05 Hamilton Mercedes 1:30.822 +2.593 41 laps
06 Bianchi Marussia 1:32.222 +3.993 25 laps
07 Sutil Sauber 1:36.571 +8.342 69 laps
08 Rosberg Mercedes 1:36.951 +8.722 91 laps
09 Kobayashi Caterham 1:43.193 +14.964 54 laps
10 Kvyat Toro Rosso 1:44.016 +15.787 9 laps
11 Ricciardo Red Bull 1:45.374 +17.145 7 laps
Gallery: The Final Day At Jerez
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