Competing against the best high school girls milers at Sunday’s Nike National Championships, La Jolla’s Chiara Dailey scorched a time of 4:34.89 to finish second overall.

This came two days after she won the U-20 3,000-meter run in 9:52.25 on the University of Oregon’s Hayward Field track.

“Running a personal record and finishing second in the mile made me happier than winning the 3,000,” Dailey said by phone after the race. “I came in hoping for a PR and to run fast, but I knew (race winner Elisabeth Barada) was a half-miler, so I made my move early to try to discourage her.

“I saw my time at the finish line, and that made me very happy.”

Dailey’s time is the fastest ever run by a San Diego Section girls miler — converting to a 4:33.29 for 1,600 meters. It was a four-second improvement over her time of 4:39.14, converted to 4:37.08 for the 1,600, clocked at last year’s HOKA Festival of Miles.

Ideal racing conditions greeted the runners on a sunny, 75-degree day.

The Stanford-bound Dailey immediately sprinted into the lead in the Nike mile, going through the first 400 in 1:07.68 and 2:18.16 for the 800. She then attempted to break the field by speeding up with a 1:09.76 on the third lap, leaving all but Indiana’s Barada far in her wake.

With just over 200 meters remaining, Barada, who ran very sparsely this spring, accelerated past Dailey heading into the final turn. Then Dailey made a counter move off the turn that Barada matched to win by less than a second in 4:34.25.

Dailey posted a negative split in the race, clocking a 2:18.16 for the first half and 2:16.73 over the final 800.

Barada, who will attend North Carolina in the fall, came into the race fresh while Dailey warmed up by rolling to the U-20 3,000 title on Friday, winning by 15 seconds as the only runner in the field to break 10 minutes.

With the victory and fast time, Dailey qualified for the World U-20s, which will be held in Eugene, Ore., starting Aug. 5.

But she said first she’ll take a couple of weeks off from competition before starting to build back up for the U-20s.

“We’ll celebrate tonight,” she said.