LONDON -- Not even a return to Wimbledon could pull Eugenie Bouchard out of her tailspin.

Bouchard lost for the 12th time in 14 matches on Tuesday, falling to Chinese qualifier Duan Ying-Ying 7-6 (3), 6-4 in the first round.

In the post-match press conference, Bouchard said she is suffering from a grade 2 abdominal tear but didn't want to miss the match.

Bouchard reached the Wimbledon final last year and hoped a return to the All England Club could turn around what has been a miserable 2015 season.

Instead she lost in straight sets to a player ranked 117th in the world.

Last year, Bouchard reached the semifinals at the first three Grand Slam tournaments of the season.

The 21-year-old from Westmount, Que., looked like she was in for another strong season in 2015, opening with a run to the quarter-finals at the Australian Open.

It's been nothing but disappointment since, with losses in the first round of the French Open and now Wimbledon.

Fellow Canadian Vasek Pospisil fared better then Bouchard. Vancouver's Pospisil beat France's Vincent Millot 7-6 (2), 3-6, 6-7 (4), 7-6 (4), 6-3.

Earlier, defending women's champion Petra Kvitova and former men's winners Roger Federer and Rafael Nadal all won their first-round matches at Wimbledon in straight sets and in rapid-fire fashion.

Of the three, only Nadal lost serve and the big names imposed themselves with ease on Day 2 of the grass-court Grand Slam as London basked in warm, sunny conditions.

In keeping with Wimbledon tradition, Kvitova had the honour of playing the first match on Centre Court on the second day as the reigning women's champion.

The second-seeded Czech wasted no time in reasserting her dominance on her favourite court, overpowering Kiki Bertens of the Netherlands 6-1, 6-0 in just 35 minutes.

Kvitova won 28 of 29 points on serve, with the only blemish coming when she double-faulted on the first point of the final game, hitting a 93 mph (150 kph) second serve just wide. She won the next four points, finishing -- appropriately -- with a service winner.

While Kvitova was happy to sail through so quickly, she felt bad for her parents, who were guests in the Royal Box and got to see their daughter play for barely more than half an hour.

"I have to say sorry to them," she said, smiling. "I think they are happy anyway."

Federer, the seven-time men's champion, followed Kvitova on Centre Court and also made quick work of his opponent. The second-seeded Swiss needed just 68 minutes to dispatch 88th-ranked Damir Dzumhur of Bosnia 6-1, 6-3, 6-3.

Federer, bidding to become the first man to win eight Wimbledon titles, broke five times and never faced a break point.

"I was happy I played aggressive," he said. "I must say I'm very happy, always, to win like that."

Federer, who has won 17 Grand Slam titles, is playing in his 63rd consecutive major.

"Somehow the streak is still alive and I'm also very proud of the fact that I never retired from a match once it started," he said. "Those two stats I care about and hope I can keep them up for the remainder of my career."

Nadal, the two-time champion, coasted to a 6-4, 6-2, 6-4 win over Thomaz Bellucci of Brazil on Court 1. He hopped in the air and pumped his fist after completing the victory.

"Here the feeling in Wimbledon is so special, and playing on grass, too," Nadal said. "So always is very emotional when you hit some good shots in this beautiful club."

Nadal, who lost in the first round of the Wimbledon warm-up at Queen's Club and has slipped to No. 10 in the rankings, was broken twice and was credited with fewer winners (21) than unforced errors (23) but still was never seriously troubled.

"In general, it was a very positive victory," the Spaniard said. "Straight sets. Not bad feelings."

Another former champion, 2013 winner Andy Murray, was playing the third match on Centre Court, facing Mikhail Kukushkin of Kazakhstan.

In another one-sided women's match, 10th-seeded Angelique Kerber swept fellow German Carina Witthoeft 6-0, 6-0 -- the third "double bagel" in two days.

On Monday, both Venus Williams and Andrea Petkovic won their matches 6-0, 6-0. Those were the first double bagels at Wimbledon in six years.

Kerber said the scoreline of the 44-minute match was misleading.

"I think it was a good match for me," she said. "Carina was playing not bad, actually. So the games (were) not like 40-0. It was very close, actually."

Other men's winners Tuesday included No. 13 Jo-Wilfried Tsonga, No. 20 Roberto Bautista Agut, No. 22 Viktor Troicki, No. 23 Ivo Karlovic, No. 25 Andreas Seppi and No. 30 Fabio Fognini.

Jack Sock, the 13th-seeded American, was knocked out by Sam Groth of Australia, 6-3, 3-6, 6-3, 6-3.

Among the women, No. 17 Elina Svitolina and No. 20 Garbine Muguruza advanced to the second round.

-- With files from The Canadian Press.