MELBOURNE — A shirtless Rafael Nadal looks over his shoulder in the black-and-white photo, his biceps flexed and muscles rippling.

Nadal might be one step closer to his vaunted Rafa Slam, but he’s also an Armani model. The photo will appear in a campaign launch next month. First, however, there’s some tennis at hand, and Nadal is doing just fine as an advertisement for his sport.

He improved his winning streak to 25 matches in Grand Slam events yesterday, as he ousted No. 15 Marin Cilic 6-2, 6-4, 6-3 in the fourth round at the Australian Open.

Nadal already holds the French, Wimbledon and U.S. Open crowns and hasn’t lost in a major since the last year’s quarterfinals at Melbourne Park. Nobody has held all four men’s majors at once since Rod Laver in a calendar year in 1969.

Nadal’s victory sets up a quarterfinal against fellow Spaniard David Ferrer, who beat 20-year-old Canadian qualifier Milos Raonic 4-6, 6-2, 6-3, 6-4.

In the night’s last match, Kim Clijsters wasted plenty of chances to break Ekaterina Makarova before winning 7-6 (3), 6-2.

Defending champion Roger Federer defeated No. 19 Stanislas Wawrinka 6-3, 6-3 in the first all-Swiss quarterfinal at a Grand Slam.

In the women’s quarterfinals, Caroline Wozniacki rallied from a set and a break down to beat Francesca Schiavone 3-6, 6-3, 6-3 and secure her spot in the semifinals — and at the top of the rankings.

Wozniacki will face Li Na, who beat Andrea Petkovic to reach back-to-back Australian Open semis.