Estremadura withstood a challenge by Manco Capac II at the 17th and final jump, then pulled away to win the 40th running of the Middleburg Bowl by five lengths today with Bannacheck II third another nine behind.

On a day when most other races equalled those seen at midseason hunt meets, Estremadura's victory over Manco Capac II, last year's winner, was the plum.

"He jumped like a pro," said Mike DuPont, the 10-year-old Gustav gelding's owner and rider. "I was most proud of him at the last fence when Manco came at him we feared him, but he took it flat and loose and then we went flat out."

"It was a fast race," added DuPont, "about the fastest I think I've ever gone."

Five good timber horses started the race, with the winner covering the 3 1/4 miles in 7:01. Bannacheck II was responsible for much of that speed, dueling with Breaking Dawn and Gran Vital over the early fences.

It was the first start of the season for Manco Capac II, a lightly raced jumper. But, as usual, Virginia's top horse in 1978 turned in a superior performance before a Middleburg point-to-point crowd of more than 5,000.

Dupont was not as successful in his attempt to win an unprecedented double in the two major timber races. In the earlier Middleburg Hunt Plate Hami tired badly after the first turn and came in fourth behind an extremely good looking newcomer to timber racing, Salvo.

Ridden by Randy Waterman, Salvo was a clear winner with Too Far Gone and Boca Bird following.

Waterman won two other races - the Janneys Mill Bowl with Worthy of Love and the Louis Leith Cup with Champerty, the latter after a stirring duel through the three miles with Jon Ruhsam on Sabinus.