Lewis Hamilton laid down a marker in this year's championship battle, beating Sebastian Vettel in a head-to-head fight in a Spanish Grand Prix classic.
The Briton lost the lead to the Ferrari driver at the start, but, using an alternative strategy, was able to re-pass the German into Turn 1 after a Virtual Safety Car brought the pair back together on track.
Tyre choice proved crucial as Hamilton decided to stay out much longer than Vettel in the opening stint, with the likelihood being the Mercedes on a two-stop plan with the Ferrari on a three. A decision to use the slower medium compound in the second stint also paid off for the three-time world champion, as he switched back to the soft rubber as the VSC was ending, a lap earlier than Vettel who had to use the slower tyre.
That meant when the two were side-by-side as the Ferrari exited the pits, though Sebastian was able to strongly hold off the first attack from Hamilton, the extra grip and DRS saw the Mercedes ease ahead into Turn 1 before maintaining a gap to the Prancing Horse a claim his second win of the season.
It was a race of attrition behind, as Daniel Ricciardo emerged in third for Red Bull. That followed his team-mate Max Verstappen and Kimi Raikkonen being eliminated at the first corner on Lap 1, as the second Ferrari was hit by Valtteri Bottas on the inside, sending his countryman into the Dutchman and damaging both their front suspensions.
Bottas was able to continue, indeed holding up Vettel briefly after his first pit-stop, but an old engine that had to be used due to a problem on Saturday morning finally failed in its fifth straight race.
With half of the top six cars out, that allowed the midfield teams the opportunity to score some solid points. Once again it was Force India who fully capitalised with Sergio Perez fourth and Esteban Ocon fifth, further cementing their grip on fourth in the Constructors' championship as Williams failed to score.
Nico Hulkenberg made up for a disappointing qualifying to claim sixth for Renault and Toro Rosso had their best race of the season with local favourite Carlos Sainz moving up to seventh and Daniil Kvyat making the most places of anyone on the day, finishing ninth from 19th on the grid.
In between them, Pascal Wehrlein scored crucial points for Sauber, leaving McLaren bottom of the teams' standings. The German did finish seventh on track but a five-second penalty for entering the pit-lane on the wrong side of the bollard dropped him behind the Spaniard.
Completing the top 10 was Romain Grosjean for Haas, but it almost a lot better for the American team as Kevin Magnussen ran ninth before a puncture, gained trying to pass Kvyat, forced the Dane to pit on the penultimate lap and sending him out the points.
It also promoted Marcus Ericsson to 11th with Fernando Alonso in 12th, as his hope for points was ruined by a collision with Felipe Massa in Turn 2 on the opening lap. The Brazilian would also be involved in the incident that caused the pivotal VSC, as Stoffel Vandoorne hit the side of him at Turn 1 leaving the Belgian in the gravel, en route to 13th.
Jolyon Palmer and Lance Stroll would complete the finishers in 15th and 16th respectively, behind the aforementioned Magnussen.
In the championship, Hamilton closed the gap to Vettel back to just six points, in the Constructors' too Mercedes increased their lead to eight points heading into the Monaco Grand Prix in two weeks time.
