Ahead of Saturday’s intense qualifying session for the United States Grand Prix, Red Bull‘s Sergio Perez topped Formula One’s final practice. Although the session was largely drama-free, an earlier flare-up between championship leaders Max Verstappen and defending champion Lewis Hamilton did leave the viewers excited.

Currently, Verstappen leads Hamilton by six points in the championship and was third-fastest in the session. Both Verstappen and Perez’s strong practice sessions show that Red Bull is ready to compete at the Circuit of the Americas. Hamilton and Mercedes have dominated on the permanent road course, but Hamilton was only sixth on the speed chart ahead of qualifying.

The rivalry between Verstappen and Hamilton flared Friday in practice when Verstappen flipped a middle finger at the seven-time champion and called him a “stupid idiot” as the two raced down the starting grid straightaway.

Verstappen is chasing his first championship. Hamilton has won a record-tying seven titles, including the last four.

Hamilton has won the U.S. Grand Prix at COTA five times since it opened in 2012. His Mercedes teammate Valtteri Bottas won in 2019. The race was cancelled last year by the coronavirus pandemic.

Alpine said before practice it had changed the power unit for Fernando Alonso following a failure Friday. Alonso will start Sunday’s race at the back of the grid.

Both championship contenders had a difficult final practise session, with Red Bull having to replace the rear wing on Verstappen’s vehicle after detecting a hairline fracture, and Hamilton reporting rear-end stability issues.

It’s difficult to say which team has the upper hand coming into qualifying because neither Verstappen nor Hamilton have managed representative times.

Lando Norris of McLaren was two-and-a-half tenths slower than Perez in fourth, ahead of Mercedes’ Valtteri Bottas and Hamilton in fifth and sixth.

With inputs from the Associated Press