Straight And True removed any remaining doubt that the 1976 Eclipse Award winner was back on his championship track yesterday by winning the National Steeplechase Handicap by three-quarters of a length over Deux Coup before a Fair Hill closing-day crowd of nearly 12,000.

Al Quanbeck got Tall Award in third, with Early Mor fourth. Fire Control and Un Adios rounded out the exceptionally fine field in that order.

Mrs. Ogden Phipps' handsome dark-brown gelding made it two in a row at the Fair Hill spring meeting, its third victory in a now counting a win at Radnor on a disqualification. It also was the sixth time this spring the 8-year-old has been in the money after its disastrous year in 1977 when the gelding went unplaced in eight starts.

Bill Martin, a 28-year-old apprentice jockey, held Straight And True in third place throughout most of the 2 7/16 mile, 15-jump test.

Martin made his move going into the final three jumps. "We were jumping like there weren't any fences," he said. "We went inside becasuse there wasn't anywhere else to go."

Tommy Skiffington on Deux Coup and Martin put on an Affirmed-Alydar duel down the stretch, with Martin using the whip to advantage.