PARIS (AP) -- Sam Querrey says he won Sunday at the French Open because he didn't care if he lost.
The highest-ranked American on the men's tour credited a more positive attitude for a first-round victory over Lukas Lacko of Slovakia 6-3, 6-4, 6-4. Merely by winning a match, Querrey equaled his best showing ever at Roland Garros.
"I just focused on my attitude out here today and played the best match I've played all year on any surface," he said.
Ranked 20th, Querrey came into the tournament with a 1-3 record during the clay-court season. He decided to try a different mental approach against Lacko.
"I felt no pressure," he said. "I went out there with the attitude that I don't care if I lose. I just wanted to make good decisions and be positive."
Has he tried that approach at other tournaments?
"No," he said. "But I'm going to now."
Americans have endured some dismal days in recent years at the French Open - and Sunday brought losses for four U.S. players, including an ailing Venus Williams - but there were some wins as the year's second major tennis championship began.
Top-ranked Serena Williams, Venus' younger sister, eased the sting of a first-round loss in 2012 by beating Anna Tatishvili of Georgia 6-0, 6-1. Mallory Burdette continued her ascent since leaving Stanford last year with a successful Roland Garros debut, beating Donna Vekic of Croatia 6-3, 6-4.
Shelby Rogers, who turned pro in 2009, also made her French Open debut and earned her first victory in a major event by beating Irena Pavlovic of France 6-3, 6-4. Rogers started the year 0-6 before earning a wild card to Roland Garros three weeks ago.
"It was really tough for a while," she said. "I wasn't a very happy person. But I kept grinding it out every day, and I knew something had to turn around eventually. Here I am - pretty much the highest point of my career."
Qualifier Grace Min, though, was beaten 4-6, 6-4, 7-5 by Galina Voskoboeva of Kazakhstan, and 30th-seeded Venus Williams couldn't set aside lower back pain that made it difficult to serve in a 7-6 (5), 6-7 (4), 6-4 loss to Urszula Radwanska of Poland.
In men's play, American qualifier Denis Kudla was eliminated by Jan Hajek of the Czech Republic 6-2, 5-7, 6-0, 6-4. James Blake, a 33-year-old playing at Roland Garros for the ninth time, won one scrambling exchange after hitting a shot between his legs with his back to the net, but lost to Viktor Troicki of Serbia 6-4, 6-2, 6-2.
"The difference between my best and now is consistency," Blake said. "I'm still trying to work on it. There are days it is good. Today wasn't one of my best days. Off days are exposed very quickly out here."
Absent from the American contingent was No. 41-ranked Mardy Fish, who has been dealing with heart problems.
The French Open has been the toughest Grand Slam for American men. They've won four Roland Garros titles, compared with 19 at the U.S. Open, 15 at Wimbledon and 14 at the Australian Open. Last year, only three of eight U.S. men won in the opening round.
Querrey had been eliminated in the first round at Roland Garros five times, and his only previous victory in the tournament came in 2011 on remote Court 7, where he played again Sunday.
"That's the only court I can win on here," he said with a smile.
In truth, he credited his performance not to the setting, but to a better frame of mind.
"My attitude has gone up and down in the past," he said. "I felt like lately I was a little bit down, so I just tried to be extra positive and extra upbeat today. ... Even when you win a match you probably win 53 or 54 percent of the points. There is a big chunk you'll lose. You've just got to let it go. That's all I focused on out there."
At his postmatch news conference, the big-serving Querrey had a bag of ice on his right elbow. He hit 10 aces, lost only six points on his first serve and said he has the game to be successful on clay.
Burdette feels the same way. Her ranking has climbed to a career-best 80th from 142nd at the start of the year, and she snapped a string of three consecutive clay-court losses this spring by beating Vekic.
Burdette said she has enjoyed learning how to play on the slow surface.
"It's a bit of a challenge," she said. "You have to change up your strategy a little bit, especially if you're a big hitter. It takes a little bit of effort, but it's fun."
Burdette is part of a resurgence by Americans on the women's tour. Women from the U.S. outnumbered those from France in the 128-player draw with 15 entrants, three more than last year.
"The quality over the past year has jumped tremendously with the U.S. players," Serena Williams said. "They're all really young, so there is still an opportunity to grow."