Max Verstappen was forced to take on a new rear wing during final practice for the United States Grand Prix after a hairline crack was discovered in the component.
Red Bull team principal Christian Horner suggested the issue had been caused by the bumps in the circuit, despite a new surface laid to overcome complaints made after MotoGP's visit.
It failed to deter championship challenger Verstappen from finishing two-tenths of a second behind Red Bull team-mate Sergio Perez who finished quickest around the Circuit of the Americas for the second consecutive session.
Horner had stated during the hour-long outing that gains had been made overnight on the RB16B, and so it proved as the team is now firmly in the mix in qualifying after Mercedes had looked unbeatable after FP1.
As in FP2, though, Perez was fortunate to find himself out in front but for both Verstappen and Mercedes' Lewis Hamilton exceeding track limits.
Perez topped the timesheet with a lap of one minute 34.701secs, with Verstappen 0.318s quicker but for running slightly wide at turn 19.
Hamilton was 0.243s faster than the Mexican but was wide at turn nine, leaving him down in sixth position come the conclusion of the session, 0.518s behind Perez.
Separating the two Red Bull drivers as Verstappen was third overall was Ferrari's Carlos Sainz, 0.104s behind Perez.
Track conditions were tricky throughout due to strong winds and temperatures of almost 29 degrees, with a high of 31 expected for qualifying which could push the track temperature close to 50 degrees.
After such a strong showing in FP1, when Bottas and Hamilton were over nine-tenths of a second quicker than Verstappen, Mercedes now appear to be on the back foot at a circuit where it has won five of the last six races.
Behind Verstappen, McLaren's Lando Norris was fourth overall, followed by Bottas, with both around a quarter of a second adrift of Perez.
Bottas will start the race with a five-place grid penalty for taking on a sixth internal combustion engine of the season.
The second McLaren of Daniel Ricciardo followed Hamilton, with Pierre Gasly in his AlphaTauri, Ferrari's Charles Leclerc and Alpine's Esteban Ocon rounding out the top 10, with the latter a second back.
Sebastian Vettel and George Russell, who will both start at the back of the grid due to taking power unit penalties, were 11th and 12th respectively for Aston Martin and Williams.
Another driver who will serve a PU penalty and join Vettel and Russell at the rear in Alpine's Fernando Alonso was a lowly 17th, 1.789s down.
For the third successive session, Haas' Nikita Mazpein was slowest, a staggering 28 seconds back but due to the fact numerous lap times were deleted.
United States Grand Prix final practice session times
1. Sergio Perez [Red Bull] 1:34.701
2. Carlos Sainz [Ferrari] +0.104
3. Max Verstappen [Red Bull] +0.211
4. Lando Norris [McLaren] +0.244
5. Valtteri Bottas [Mercedes] +0.287
6. Lewis Hamilton [Mercedes] +0.518
7. Daniel Ricciardo [McLaren] +0.644
8. Pierre Gasly [AlphaTauri] +0.697
9. Charles Leclerc [Ferrari] +0.987
10. Esteban Ocon [Alpine] +1.010
11. Sebastian Vettel [Aston Martin] +1.150
12. George Russell [Williams] +1.322
13. Kimi Raikkonen [Alfa Romeo] +1.361
14. Nicholas Latifi [Williams] +1.417
15. Antonio Giovinazzi [Alfa Romeo] +1.551
16. Lance Stroll [Aston Martin] +1.691
17. Fernando Alonso [Alpine] +1.789
18. Yuki Tsunoda [AlphaTauri] +1.871
19. Mick Schumacher [Haas] +1.970
20. Nikita Mazepin Haas +28.755
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