Marin Cilic has ended Juan Martin del Potro’s chances of winning consecutive Grand Slam singles titles, beating the Argentine 5-7, 6-4, 7-5, 5-7, 6-3 in the Australian Open fourth round.

Del Potro lost to Roger Federer in the quarterfinals here last year, but avenged that by beating the 15-time Grand Slam winner in the U.S. Open final in September.

Cilic, whose best previous finish at Melbourne Park was a fourth round loss to del Potro last year, clinched it on his first match point when del Potro’s backhand went long.

The Croatian player was a quarterfinalist at last year’s U.S. Open, where he lost to del Potro.

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