Four years ago, David Oliver injured a hamstring before he even stepped on the track for the 110-meter hurdles at the world championships in Osaka, Japan, his first appearance at the event. The injury was not serious, but his disappointment was.

“You just never know when you’ll ever get the opportunity again to represent the U.S.A.,” Oliver said Saturday. “Especially in the hurdles.”

Two years later, a strained calf muscle kept him from competing at the world championships in Berlin. That, he said, marked “a down point of my career.”

Oliver did not care to extend his streak of frustration Saturday at the U.S. track and field championships with another world berth on the line. With a carefully executed, workmanlike performance in the 110 final, Oliver bulled his way to a victory in 13.04 seconds, securing a chance to pursue the world medal that has eluded him at the August championships in Daegu, South Korea.

“It feels good to be done, to be on that team,” Oliver said after beating Aries Merritt, who finished second in 13.12, and Jason Richardson, who was third in 13.15. “I just stayed relaxed, focused on not false-starting and doing anything stupid.”

Oliver’s victory capped a day in which Matt Centrowitz, a graduate of Broadneck High in Annapolis, chased down two-time Olympic medal winner Bernard Lagat to win a thrilling 1,500 final in 3 minutes 47.63 seconds; Allyson Felix won her first U.S. title in the 400, topping Francena McCorory with a time of 50.40 to 50.49; and Tony McQuay outkicked two-time world champion Jeremy Wariner in the men’s 400, finishing in 44.68 to Wariner’s 44.98.

“It’s unbelievable,” Centrowitz said.

Oliver, the 2008 Olympic bronze medal winner, looked unstoppable. A former football player at Howard University, Oliver stands 6 feet 2, weighs 205 pounds and has shoulders broad enough to play linebacker. When he’s barreling down the track, it appears more likely he will bust through a hurdle than fall over one. The sleek and slender Allen Johnson, the 1996 Olympic champion in the event from Lake Braddock High, watched approvingly Saturday from the Hayward Field stands.

“Dave is just a naturally big guy,” Johnson said. “He reminds me a little bit of Greg Foster. The first time I saw Greg Foster, I thought, ‘That guy is huge.’

“The first time I raced [Oliver] — the first time I remember racing him — was in 2006,” Johnson said. “He’s come a long way. He’s put in a lot of hard work. It shows in his technique, and it’s showing in his times. He’s so consistent. He can run fast whenever he wants to.”

After playing it safe here, Oliver would like to drop a huge time in Daegu. He set the American record in the event last July, notching a time of 12.89. The world championships will give him a chance to chase Dayron Robles’s two-year-old world record of 12.87.

Getting ready for that hunt will be the focus of the next two months. Oliver said he didn’t get much pre-race advice from his coach, Brooks Johnson, who simply wanted him to take care of business.

“He just said, ‘Get on the team so we can get the hell out of here and get back to practice.’ ”

Indeed, Johnson said, he prepared Oliver to be fit here so he could survive the physical rigor of running three rounds. Speed was not the primary concern, but Johnson wants Oliver in peak shape for speed by the time the world championships kick off.

“In 2008, we brought him here to the Olympic trials super sharp,” Johnson said. “We tried not to do that this time. We have eight weeks to get him super sharp for Daegu. We will go back to the woodshed a bit.”

Felix will be getting back to work, too — she’s just not quite sure yet what will be the focus of her attention. She completed a hat trick of U.S. titles Saturday, becoming the first woman to earn U.S. championships at the 100, 200 and 400. She entered the 400 this year largely because she had a bye into the world championship 200 as the defending champion, but she has not decided yet whether to attempt a 200-400 double in Daegu.

The fact that the 400 takes place before the 200 concerns her, she said. She fears being fatigued entering the 200, an event in which she is seeking her fourth world title.

“That’s the thing that makes it toughest for me to decide, is not being fresh for the two,” Felix said.

Oliver will have no such wrestling: He knows he is going for gold. He was thrilled Saturday to have secured that long-awaited chance.

“The most important thing for me is to make it through these championships and be on that team,” Oliver said. “The U.S. championships are hard. We left probably about five people here who can go and make the world championship final.”