In a possible preview to the Pan American Games trial in June, Russell Rainer flipped Jim Howard over his head in a last-second takedown to narrowly win the 125.5 pound Greco-Roman title in the Potomac Valley AAU wrestling meet yesterday.

Rainer, a junior at the University of Richmond, was something of an unknown at the meet despite winning two gold medals at the 1977 Maccabiah Games and being a five-time Virginia state champion.

"I don't think my win was an upset although Jim Howard is the best in this area," Rainer said. Howard, 26, of the Marine Corps, was a member of the U.S. team in the world championships in 1977 and was an alternate in 1978.

Howard was slightly ahead through much of the bout. When it was announced there were 12 seconds remaining, Howard led, 10-8. With four seconds left, Rainer managed to get under Howard and heave him to the mat for three points.

"I slacked off because I figured, 'What could happen in 12 seconds?" said Howard, who is coming off elbow surgery. "I don't want to take anything away from Russell, though-he's readlly tough."

Howard had a scratched face afterward and said he also suffered a possible pinched nerve in his back on the last flip.

Rainer, looking comparatively fresh despite the last-second effort, said he'll be ready for Howard in the Pan American Game trials. "I didn't know what he liked to do today, but I think I'll have an easier time against him in the trials. I didn't use many of my moves today...I'll have a much easier time."

Rainer hopes to make the 1980 U.S. Olympic team as a Greco-Roman specialist. Greco-Roman wrestling prohibits below-the-waist holds. In today's meet, Rainer also won the open division freestyle championship.

In other weight classes, Lewis Dorance of the Marine Corps captured both open division titles in the 114.5 pound division.

Al Marshall of Navy won the open division 180.5 pound class in both free style and Greco-Roman, was named the outstanding Greco-Roman open division wrestler while Dave Hopkins of the Seneca Valley Wrestling Club was named the outstanding open-division freestyle wrestler for his victory in the 163 pound division.