Rookie Bobby Martinez has taken out the Billabong Pro at Mundaka, Spain but legendary American Kelly Slater has clinched an unprecedented eighth world surfing title.

Slater, 34, ensured he would seal yet another world title with two events still left on the tour by defeating nearest championship threat Joel Parkinson of Australia in the semis and winning through to a final showdown with fellow American Martinez.

The 24-year-old Martinez from California is almost certain to clinch rookie of the year honours after also taking out May's Billabong Pro at Teahupoo, Tahiti.

But all eyes were on Slater.

The Florida native has made a habit of breaking surfing records since clinching his first world title in 1992 as the youngest ever champion at 20.

He is now also the world's oldest surfing champion at 34.

But Slater is yet to commit to a 13th year on the world tour.

The path to an eighth world title opened up for Slater after world No.2 Taj Burrow was upset in the quarter-finals by fellow Australian Dean Morrison.

Slater's other title threats, Australian Mick Fanning and three-time world champion Andy Irons, were eliminated from the race when they bowed out in their respective quarter-finals.

Martinez overcame Morrison in their semi-final before shocking Slater in an entertaining final in one metre waves.

The next world tour event will be held at Brazil from October 30 culminating in the legendary Pipeline Masters at Hawaii from December 8.

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