Dani Pedrosa grabbed his first win of the MotoGP season as Marc Marquez barged past champion Jorge Lorenzo at the final corner to take second place.
Lorenzo started from pole position but was passed by Pedrosa on lap five, with the Repsol Honda man able to ease away.
Pedrosa’s young team-mate Marquez was involved in running battles with Valentino Rossi and Lorenzo, finally clashing as he passed Lorenzo.
Rossi took fourth spot, with British rider Cal Crutchlow fifth.
Marquez now leads the championship standings from Pedrosa and Lorenzo, who refused a handshake from the 20-year-old after the race and was clearly angry about his aggressive passing move.
Lorenzo was all smiles at a ceremony in which the final corner at Jerez was named after him earlier this week, but it turned out to be an unhappy ending as Marquez dived up the inside.
Lorenzo was pushed off the track by Marquez’s move, but was able to recover to finish in third place.
He told BBC Sport: “I prefer not to comment on the move. I congratulate Dani for the win. And that’s it. Let’s see what happens in Le Mans.”
Marquez – who was sanctioned during his time in Moto2 for being too aggressive – apologised for the move and likened it to a similar incident at Jerez in 2005, when Rossi passed then-rival Sete Gibernau.
Marquez said: “I want to say sorry to Jorge but we have seen similar things happen in that corner before, and the most important thing was that everyone finished the race.
“If he did it to me I would be angry too but that is racing. On the last lap you have to try it.”
Lorenzo started from pole but was passed by Pedrosa off the line, only to retake the lead at turn two.
Pedrosa then took the lead and was able to open up a three-second gap by the halfway point.
Marquez saw off Rossi and then chased down Lorenzo, almost running in to the back of the Yamaha rider on three occasions.
He ran wide after his third attempt and lost ground but recovered to mount his last-lap attack.
Crutchlow, riding in pain after two crashes on Saturday, took a creditable fifth after winning a long battle with Alvaro Bautista.
In the Moto2 race, Esteve Rabat led from pole to take his first race win. British rider Scott Redding was second and is now a point behind leader Rabat in the overall standings.
The Moto3 race was red flagged on lap 17 after Alan Techer crashed heavily, one of nine riders to crash out.
Maverick Vinales was awarded the win ahead of Luis Salom and Jonas Folger. Spanish riders have now won all nine races across the three classes this season.
Spanish MotoGP results:
1. Dani Pedrosa (Spa) Repsol Honda 45’17.632
2. Marc Marquez (Spa) Repsol Honda 45’20.119
3. Jorge Lorenzo (Spa) Yamaha 45’22.721
4. Valentino Rossi (Ita) Yamaha 45’26.546
5. Cal Crutchlow (GB) Tech 3 Yamaha 45’30.295
6. Alvaro Bautista (Spa) Gresini Honda 45’32.726
7. Nicky Hayden (USA) Ducati 45’43.264
8. Andrea Dovizioso (Ita) Ducati 45’59.513
9. Aleix Espargaro (Spa) Aspar ART 46’01.444
10. Bradley Smith (GB) Tech 3 Yamaha 46’02.093
