Wawrinka finds old self to upset Dimitrov at Wimbledon

Out of form and a set down to Grigor Dimitrov after just 23 minutes, Stan Wawrinka was just about the only person on Centre Court who believed he could win.

The three-time Grand Slam champion - whose ranking has fallen to 224 following knee surgery - proved himself right, rallying to defeat the sixth-seeded Dimitrov 1-6, 7-6 (3), 7-6 (5), 6-4 at Wimbledon on Monday to claim just his second Grand Slam victory since last year's Wimbledon.

Wawrinka received a fillip earlier when his girlfriend Donna Vekic pulled off a top-10 triumph of her own, defeating fourth-seeded Sloane Stephens 6-1, 6-3.

"It was a good day for us at the office," Wawrinka said.

"That's for sure." After missing the second half of 2017 following surgery on his left knee, Wawrinka has struggled to regain his form since returning at the Australian Open in January.

The 33-year-old Swiss won just three matches across four tournaments at the start of the year, prompting him to take another three-month break.

The second edition of the comeback had been even more concerning, with just two wins in five tournaments climaxing with a thrashing from fellow long-term injury victim Andy Murray who, despite that victory, deemed himself unfit to compete at Wimbledon.

Wawrinka's prospects at the All England Club were bleak, and appeared bleaker when he was drawn against 2014 semifinalist Dimitrov in the opening round. Wawrinka had never beaten a top-10 player on grass.

"I had to put myself together again, to try to fight, try to find (a) solution," said Wawrinka of his thought process after dropping the first set.

He found it. The Swiss doubled his winner count and lifted his first-serve percentage to level the set score through a tiebreaker, and toughed out a high-quality third set via the same method.

Wawrinka's serve carried him to a 5-4 lead in the fourth, before he pounced on his first opening of the set to seal victory.

Vekic said after her win over the U.S. Open champion: "I'm really happy that I was the first one today so now I can watch him a little bit. It's not easy when there's two matches in one day, we're both kind of a little bit stressed but it's good if we both win."