CARSON, Calif.—The sweltering heat of southern California brought out the best yet in Jenn Stuczynski.

The 25-year-old from Churchville, N.Y., broke her American record in the pole vault at the Adidas Track Classic on Sunday, outshining Tyson Gay’s sweep of the 100 and 200 meters and other strong performances by a powerhouse field at the Adidas Track Classic.

Stuczynski cleared 16 feet, 0 3/4 inches to break the mark of 16-0 she set last year in the Reebok Grand Prix in New York. Only world record holder Yelena Isinbayeva has gone higher. Stuczynski missed three times at a world record 16-5 1/2.

“I feel like she is within sights,” Stuczynski said of the Russian great, “but I still need to become a little more consistent and a little more confident, and there are still some technical things I need to work on.”

Stuczynski also broke the American record at the Adidas meet last year, only to top it again in New York.

Temperatures on the track reached 110 degrees, and it was into the 90s in the shade, in front of half-empty bleachers at the Home Depot Center.

Jeremy Wariner, at 24 already an Olympic gold medalist and two-time world champion, said he nearly pulled out of the race with a sore hamstring. But the lanky Texan decided he felt good enough to go, and won in 44.42, second-fastest in the world this year behind fellow American LaShawn Merritt’s 44.34.

Allyson Felix concluded an emotional week with a disappointing fourth-place finish in the 100. She withdrew from the 200 under orders from her coach Bob Kersee, who felt she was too drained after returning from Doha, Qatar, last Saturday, attending the funeral of her boyfriend hurdler Kenneth Ferguson’s father in Detroit and participating in graduation ceremonies at USC on Saturday.

In a race that featured seven of the 10 fastest women last year, reigning Olympic gold medalist and world champion Veronica Campbell-Brown of Jamaica won the 100 in 11.14, edging American Lauryn Williams by .01 seconds. The same runners finished 1-2 at last year’s worlds, as well. Marshevet Hooker was disqualified after the event’s second false start.

Bernard Lagat survived a NASCAR-like crash at the start to pull away at the end and win the 1,500 in 3:35.13 seconds. The start was recalled after 85 meters when Lopez Lomong and Nate Brannen tumbled to the track. Nick Symmonds got a gash in his right knee when he was spiked trying to hurdle Lomong’s feet and pulled out of the race early.

“It reminded me of the 2004 Olympics when I had my Kenyan friend do a false start, so some fresh memories came back,” Lagat said. “When something like that happens you have to recoup again real quickly. You have no time to waste. You have about 15 seconds to re-start the race with the same focus.”

The Kenyan-born Lagat won his first world titles, in the 1,500 and 5,000, last year in his first international competition as a member of the U.S. team.

Gay won his first 100 of the season in 10.05 seconds and the 200 in 20.08, both into slight headwinds. He edged training partner Darvis Patton in the 100 by .01 seconds, then eased up in a one-sided victory in the 200.

Neither time was spectacular, but that didn’t bother Gay, who in two weeks is scheduled for a 100 showdown with Jamaican Usain Bolt at the Reebok meet May 31 in New York. Bolt ran the second-fastest 100 ever, 9.76 seconds, two weeks ago. It’s the only race on Gay’s schedule before the U.S. Olympic trials in Eugene, Ore., June 27-July 6.