Bottas eventually asserted himself at the top around 11:30 local time, and both teams then switched their focus to different - and slower - programmes.
Aside from the occasional flurry of fastest times, the majority of the session had been quite straightforward until Vettel brought out the first red flag just after midday.
The Red Bull was off the track at Turn 1, and it appeared to have spun as the car was facing in the opposite direction to the track, close to the outside barrier.
Vettel was looking around the rear of the car as soon as he climbed out of it, and when it was returned to the pits his Red Bull crew struggled to roll it back into the garage.
Mercedes made a late start to the final day of running, with Lewis Hamilton joining the action just before lunch after a gearbox issue robbed the team of any morning track time.
The 2008 world champion logged five laps in the short time he had before the break, setting the seventh fastest time.
Adrian Sutil clocked the most laps of the session, as Sauber gave him an extra half-day of testing to make up for only managing one lap on Saturday.
The German was able to work on a race simulation among his 91 laps, before handing over to Esteban Gutierrez for the afternoon.
For the second day running the lunchbreak started slightly early, when the Lotus of Romain Grosjean stopped on the backstraight and brought out the red (and then chequered) flag.
Pos Driver Team/Car Time Gap Laps
1. Valtteri Bottas Williams-Mercedes 1m34.797s 60
2. Fernando Alonso Ferrari 1m35.509s +0.712s 27
3. Nico Hulkenberg Force India-Mercedes 1m35.577s +0.780s 33
4. Jean-Eric Vergne Toro Rosso-Renault 1m35.701s +0.904s 43
5. Adrian Sutil Sauber-Ferrari 1m36.467s +1.670s 91
6. Jenson Button McLaren-Mercedes 1m38.111s +3.314s 20
7. Lewis Hamilton Mercedes 1m38.650s +3.853s 5
8. Kamui Kobayashi Caterham-Renault 1m38.653s +3.856s 58
9. Romain Grosjean Lotus-Renault 1m39.302s +4.505s 25
10. Sebastian Vettel Red Bull-Renault 1m39.708s +4.911s 44
11. Max Chilton Marussia-Ferrari 1m41.242s +6.445s 10
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