Wawrinka upsets Dimitrov after girlfriend Vekic ousts Stephens

Three-times Grand Slam champion Stan Wawrinka returned to the big stage in style on Monday, ousting sixth seed Grigor Dimitrov 1-6, 7-6(3), 7-6(5), 6-4 on Centre Court at Wimbledon.

The win followed the triumph for Wawrinka's girlfriend Donna Vekic, who demolished fourth seed Sloane Stephens on Court One.

"I think it was a good day for us at the office, that's for sure," Wawrinka told reporters. "Was great match from her. I watch it from home before coming back for my match."

The Swiss former world number three, whose ranking had dropped to 225 after a knee injury, fought a stubborn and determined match from the baseline to down the 27-year-old Bulgarian, who appeared beset by first-round nerves.

It was a tough draw for Dimitrov but it looked like being a straightforward task for him after he wrapped up the first set in less than half an hour.

Wawrinka is nothing if not tenacious, however, and he fought for every point, becoming more and more comfortable as the match went on.

By contrast Dimitrov became more tense and inconsistent. He failed to convert two set points in the second set and that knocked his confidence, allowing Wawrinka back into the match.

Dimitrov suffered again at the end of the third set. After breaking serve early, he dropped his own while serving for the set. Former Wimbledon champion John McEnroe, who was commentating, described it as choking.

Wawrinka's long experience paid off in the two tiebreaks. The 33-year-old, who has won every Grand Slam except Wimbledon, was steady and cool, sending down rasping groundstrokes from both sides of the court.

His intensity and focus continued into the fourth set, which he captured on Dimitrov's serve when the Bulgarian could only tip a powerful return into the net.

Wawrinka said he never lacked motivation despite his long rehabilitation.

"I know where I've come from with my injury, I know all the work I've been doing. It's because I'm still really motivated to play any player, any court," he said.

The Swiss said his knee had held up well but he was sure he would be tired after the match which lasted two hours 45 minutes.

"Mentally was the toughest part today. That's where I'm the most tired, for sure. Then it doesn't help for your body...

"I should be okay, completely fine for my next match in two days."

A crest-fallen Dimitrov said it was hard to take defeat so early in the tournament.

"He fought very hard. He deserved way more to win today than me," the Bulgarian said.

"When it came to the clutch moments, he seized those moments, simple as that. He served big when he had to, hit the big shots when he had to."

Dimitrov, who won the season-ending ATP championship last year, said he felt he had been practising well.

"Maybe I can't deal with the pressure right now and I want too much from myself," he said.