Julianne McNamara, a 15-year-old gynmast from Danville, Calif., ranked fourth on the 1980 U.S. women's Olympic Gymnastics team, won the all-around title in the Capital Gymnastics Invitational tournament at George Washington University's Smith Center last night, defeating fellow Olympian Tracee Talavera, 15, of Walnut Grove, Calif., and defending champion Shari Mann, 15, of Potomac, Md.

McNamara and Talavera were tied going into the last event, the floor exercise. McNamara scored 9.60 and Talavera 9.05.

Overall, McNamara scored 38.15, Talavera 37.60 and Mann 37.45.

"I've been working on that floor routine since last November, " McNamara said.

"I feel pretty good now, but I'm tired. I've been in two tournaments in the last few weeks, one in Texas and one in Florida. My foot's been a little sore and I've had to watch it."

"I think I did a good job," said Mann, who last year won the first Capital Gymnastics title over Olympian Lisa Zeis of Cheektowanga, N.Y. Mann trains at the MG Gymnastics Center in Silver Spring.

On the uneven bars, normally her strongest event, Mann lost critical points. Attempting a free hip handstand to a hecht with a back flip out, she lost her grip on the high bar with one hand for a fraction of a second.

She has scored several 10s in this event, but last night she made only 9.3 -- only respectable. Talavera, the event's winner, had a 9.6, McNamara a 9.5.

A difficult and flawlessly executed 1 1/2 pirouette over the high bar followed by a toe-on full back flip capped that event for Talavera, giving her one-tenth of a point over McNamara's bar routine, which included a free hip front flip dismoount.

That tied the score after the second of the meet's four events. McNamara had beaten Talavera by one-tenth of a point on the vaulting exercise, 9.35-9.25, to begin the meet.

On the balance beam, Talavera, ranked No. 1 on the 1980 U.S. women's Olympic gymnastics team, and McNamara tied, each with an impressive 9.7, to leave the outcome of the meet to be decided in the final event.

Both gymnasts delighted the crowd in the half-filled Smith Center with their beam routines, Talavera with aerial cartwheels, two and three consecutive back handsprings and a single full twist dismount; McNamara with a press handstand mount, two back handsprings, a back flip in a pike position and a cartwheel full twist off.

Leading off the floor exercises, Talavera stumbled forward slightly near the beginning of her routine, brushing her head briefly on the canvas and marring a near-flawless exercise that included back handsprings, a double full twist and a double back flip.

McNamara, with a round off back handspring, a double back flip and triple double full twists, captured that final event and the meet with a score of 9.6. d

Mann won the vaulting event with a 9.45, vaulting onto the horse with a full twist and executing a full twist off.

Kathy Johnson, 21, of Atlanta, ranked No. 2 on the U.S. women's Olympic Gymnastics team, had been scheduled to compete, but bowed out at the last minute.