At 19, Renaldo Nehemiah has achieved undisputed dominance of the high hurdles. Now he is turning to coaching, with a most impressive pupil.

Nehemiah, appropriately wearing No. 1 on his jersey, destroyed a tough field in the 60-yard event at the 91st National AAU Indoor Track and Field Championships tonight, setting a meet record of 6.94 seconds and maintaining his perfect record this winter.

Then Candy Young, a 16-year-old high school junior from Beaver Falls, Pa., twice posted a world indoor record of 7.50 seconds in the women's 60-yard hurdles, each time edging the former record-holder, Deby LaPlante.

Between Young's semifinal and final races, she was the beneficiary of some advice from the cool, confident Nehemiah.

"He told me not to change anything tonight, but when I go back to practice Monday to bend my lead leg," Young said. "I know him, but I never talked to him before. It wasn't like we were strangers. I've talked to his coach (Frank Costello) before."

After Young's semifinal success, in which LaPlante was timed at 7.51, LaPlante tried to beat the gun in the final and was recalled. She then clocked 7.52, one-hundredth better than her previous indoor record.

"I thought we started out together and we were even until the last hurdle," Young said. "Then I used my strength to win. I started working on my lean about three weeks ago and that's all I've been practicing."

Young's official coach at Beaver Falls is Karlin Ryan, who claims his role as Joe Namath's backup quarterback in high school has been eclipsed by Young's fame.

Nehemiah ran three times today, then grabbed a train for Maryland, where he will compete Saturday in the Atlantic Coast Conference meet at Cole Field House.

"Tomorrow, I just want to stay healthy and have a good time. and show them an all-around athlete," Nehemiah said. "Tonight, the crowd (13,087) at the Garden was enough incentive. I wanted to run 6.9 to prove how consistent I can be -- a world record or close to it each time."

Nehemiah ran a quarterfinal in 7.19 at 2.25, a semifinal in 7.07 at 5 p.m. and a final in 6.94 at 7:25. He had a rocky road in the semifinal, although his time cut four-hundredths of a second off Charles Foster's 1978 meet record.

"I went back to the hotel and lay down after the semifinal," Nehemiah said. "After my first race, I spent the time sitting and eating, which I won't do any more, because I felt kind of flat."

Jan Merrill didn't feel good, either, after a tremendous double, 35 minutes apart, in which she was twice beaten by inches.

Julie Brown set a meet record of 9:46.1 in nipping Merrill in the twomile, then Francis Larrieu barely held off her archrival to capture the mile in 4:39.2.

The best of the men's races was the 1,000, in which unheralded Evans White, a television addict from Prairie View, upset Mark Belger with a strong kick in 2:08.4.

"I've been watching him on TV for the last two races," White said, "and he ran both the same way. He has a tendency to lay back until the last two or three laps and explode. I figured if I stayed up front and kicked, I'd win. I'm underrated, maybe because it's a small school, and I don't get to run against the big schools very much."

The Philadelphia Pioneers easily retained their team championship, but D.C. International gained a measure of respect by winning the concluding mile relay in 3:15.7, as Fred Sowerby outleaned the Pioneer's Herman Frazier.

Sowerby had been nipped by the Pioneers' Mike Solomon in the 600 in a slow 1:12.4.

D.C. International broke the world indoor record in the 1,180-yard sprint medley relay, as it had hoped, but it was nothing to celebrate, because the Pioneers' team of Tony Darden, Riddick, Frazier and Bill Collins went even faster, 2:02.7. D.C. International (2:02.9) might have won, except for a horrible final baton pass from John Christian to Cliff Wiley.

Other world indoor records fell in the women's mile relay, 3:43.0 by Prairie View; the women's 60-yard dash, 6.71 by Evelyn Ashford; the women's mile walk, 6:58.9 by Georgetown freshman Chris Shea; the men's two-mile walk, 12:40.0 by Todd Scully, and the women's 220-yard dash, 23.93 by Chandra Cheeseborough.

Benn Fields won the high jump on fewer misses as he, Franklin Jacobs and James Frazier all cleared a meetrecord 7-4 3/4. Louise Ritter won the women's version at 6-2 with Maryland's Paula Girven second at 6 feet.

Riddick overhauled Houston McTear to win the men's 60 in 6.14, Marty Liquori captured the threemile in 13:14.7, Dan Ripley set a meet record of 18-1 in the pole vault and Steve Scott took the mile from Steve Lacy in a slow 4:01.4.