Bill Rodgers underscored his status as America's premier long-distance runner yesterday when he won the seventh annual Perrier Cherry Blossom 10-mile around West Potomac Park in record time.

Rodgers crossed the finish line in 48 minutes and seven-tenths of a second, shattering both his own year-old course and American records for a certified 10-mile course by nearly 57 seconds. John Flora of Boston was second, finishing in 48:15, 100 yards behind Rodgers.

Eighteen-year-old Aileen O'Connor of College Park was the first woman finisher, claiming a new American women's mark for a certified 10-mile course of 56:02. O'Connor placed 105th overall in a field of 3,200.

"I was thinking Rodgers would do a low 46 (minutes)," said Flora. "But the pace was too slow at the beginning. Anyway, everyone knew that Rodgers was going to run with the pack awhile and then take off whenever he felt like it. I though he was just toying with us."

Rodgers, 31, the defending champion in the New York and Boston martahons as well as the Cherry Blossom, took the lead at the six-mile mark.

"(Bill) Haviland broke it open at the four-mile mark," Rodgers said. "Unitl then, it had been a huge pack. I went with Haviland. We were neck and neck for 1 1/2 miles and then I sensed he was tiring a little and pushed it harder.

"I thought I could cruise then, but I looked back and there was Flora breathing down my neck. He stayed so close, keeping me so nervous, I couldn't even stop to get water.

"Flora and I haven't raced on roads much. He has beaten me indoors over two-and three-mile distances. I said to myself he'd pay for that today. But he's a gutty runner."

Flora, 23, from Boston, said his stomack "felt like rubber at the end of the race." He had never competed in a 10-miler before. He has run some 20-kilometer (12.4-mile) events, covering the first 10 miles in a personal best of 49:10. He used yesterday's race to prepare for the 10-kilometer event at the Penn Relays at the end of the month, he was 30 yards behind, but never really challenged.

Rodgers, who will spend the next two weeks doing speed work in preparation for the Boston marathon (April 16), said he worried a bit before the race because he had not trained or raced much this year.

"I like to race myself into shape," said Rodgers, of Melrose, Mass. "I hadn't raced much this year because of business commitments. But I was confident I could set a course record, although I didn'twant to go out too fast because somebody else might have had a real good kick."

Rodgers attributed the better overall times of the top finishers this year to lack of wind and cooler temperatures-the 1978 race was ru n into a stiff wind. This year, the top finishers all came in under 50 minutes, with Rodgers, Flora and Haviland of Athens, Ohio, the third-place finisher, breaking the old course record.

The 3,200 starters crowded the starting line on Ohio Drive near the Lincoln Memorial to such an extent that the runners at the rear of the pack crossed the starting line90 seconds after the gun was fired to begin the race.

"I like the 10-mile distance," Rodgers said. It doesn't take you days to recover from arace of this length."

Rodgers is a familiar figure in the winner's circle. He won 27 of 30 races last year and appeared hardly winded as he signed autographs on the backs of entry-number cards of other competitorsfor an hour.

The top two locaL finishers were fifth-plACE Jim Buell (49:05) and No. 10 Bruce Robinson (49:50), both of Silver Spring.

O'Connor, a senior at High Point High School who competes for the Catholic Youth Organization, cut six seconds off Julie Shea's course and American, record of 56:08. Shea missed yesterday's race because she was competing in Atlanta.

O'Connor was the leading woman from start to finish as she clipped more than two minutes off her previous best for 10 miles.

"I just set out to run steady 5 1/2 miles," said O'Connor, who is training forthe AAU junior nationals. "No other women passed me, so I kept a fairly steady pace."

O'Connor, who was competing in her fourth Cherry Blossom race, is also tow-time defending champion in the Road Runners Club of America Eastern Regional 10-kilometer women's race. Jill Haworth of Bowie placed third among the women (58:48), behind Cathie Twoomey of Minneapolis (58:27).