Chaz Davies avenged Saturday's defeat to Northern Ireland's Jonathan Rea in Aragon to close the gap at the top of the World Superbike Championship standings.
Welshman Davies secured a narrow victory in Sunday's second race on the Spanish circuit.
World champion Rea (Kawasaki) pressed the Ducatis of Davies and Marco Melandri in the early stages and moved in front after Xavi Fores (Aruba) slipped off.
But Davies took the lead with five laps left to win by 1.184 seconds and deny Rea his first double of the season.
Melandri was third and Alex Lowes finished a distant fourth ahead of his Yamaha team-mate Michael van der Mark.
Tom Sykes (Kawasaki) came sixth after recovering from a poor start which saw him lose five places at the first turn.
Rea's lead at the top of the championship is cut to 12 points, with Davies replacing Melandri in second place.