Baku - Nico Rosberg increased his lead in the drivers' championship when he returned to winning ways with a smoothly comfortable lights-to-flag victory for Mercedes in Sunday's European Grand Prix.
The 30-year-old German, who had seen his advantage cut to nine points after three poor races, came home comfortably clear of second-placed compatriot Sebastian Vettel of Ferrari.
His Mercedes team-mate and defending champion Lewis Hamilton came home a frustrated fifth after a race dogged by technical problems on the tricky new Baku street circuit as Azerbaijan hosted its maiden Formula One race.
After two successive wins had lifted him back into contention for a fourth title, Hamilton slipped back to 24 points behind Rosberg whose return to form brought him a 19th career victory.
Four-time champion Vettel took full advantage of an off-form day for Red Bull and drove steadily to finish ahead of Sergio Perez of Force India who passed Kimi Raikkonen in the second Ferrari on the final lap.
Valtteri Bottas finished sixth for Williams ahead of Daniel Ricciardo and his Red Bull team-mate, Dutch teenager Max Verstappen with Nico Hulkenberg ninth for Force India and Felipe Massa 10th in the second Williams.
Rosberg now has 141 points in the title race and Hamilton 117.
Results from the Formula One European Grand Prix in Baku on Sunday:
1. Nico Rosberg (GER/Mercedes) 1hr 32min 52.366sec, 2. Sebastian Vettel (GER/Ferrari) at 16.696sec, 3. Sergio Perez (MEX/Force India) 25.241, 4. Kimi Raikkonen (FIN/Ferrari) 33.102, 5. Lewis Hamilton (GBR/Mercedes) 56.335, 6. Valtteri Bottas (FIN/Williams) 1:00.886, 7. Daniel Ricciardo (AUS/Red Bull) 1:09.229, 8. Max Verstappen (NED/Red Bull) 1:10.696, 9. Nico Hlkenberg (GER/Force India) 1:17.708, 10. Felipe Massa (BRA/Williams) 1:25.375, 11. Jenson Button (GBR/McLaren) 1:44.817, 12. Felipe Nasr (BRA/Sauber) 1 lap, 13. Romain Grosjean (FRA/Haas) 1 lap, 14. Kevin Magnussen (DEN/Renault) 1 lap, 15. Jolyon Palmer (GBR/Renault) 1 lap, 16. Esteban Gutierrez (MEX/Haas) 1 lap, 17. Marcus Ericsson (SWE/Sauber) 1 lap, 18. Rio Haryanto (INA/Manor) 2 laps