After last night's tennis match, Cliff Richey looked as if he had walked through a swamp in a rainstorm. His hair and shirt were soaked with sweat, and his shoes and socks were muddied with court clay.

Playing with the usual tenacity and anguish, Richey defeated Ross Case in the second round of the Prudential-Bache Grand Champions tournament at Rock Creek Tennis Stadium. He pushed himself so hard during his 7-6 (7-4), 3-6, 7-6 (7-1) victory over Case, he complained of leg cramps afterward and had to be taken to the first aid station on a stretcher.

"It was just heat exhaustion," Richey, 39, said while being attended to by paramedics. "It's happened a hundred times before." He was not taken to the hospital.

Of the match, Case said: "It was one of those matches you play once a year. And you don't want to play another one."

The match took 3 hours 35 minutes. Richey went ahead by 5-2 in the final set only to fall behind, 6-5. But just when Richey looked like he had used the last of his strength, he fought off match point and tied it at 6.

The tie breaker was all Richey.

"What probably hurt most for me was that he started to look tired in the 12th game of the third set ," said Case, 34. "I just rallied from the base line thinking he was going to cramp up. But he came to the net on me and came back."

Ahead 5-2 in the third set, Richey was serving and led, 40-15. Case wiped away both match points, sending the game to deuce with a backhand winner off Richey's serve.

Richey seemed to fall apart after that, and Case continued to play adroitly at the net. Case's racquet seemed to stretch to the sidelines, as he stopped most of Richey's passing attempts.

After Case tied it at 5 with a forehand crosscourt winner and won all the points in the next game, Richey seemed finished. "I attacked at that stage," Richey said. "At least I made him make some shots."

In other second-day round-robin matches, Sherwood Stewart, 40, defeated John Alexander, 35, 6-4, 6-3; Stan Smith, 39, defeated Ray Moore, 39, 6-0, 7-5; Colin Dibley, 41, defeated Andrew Pattison, 37, 6-2, 6-3. Noah Out of Classic

Yannick Noah will not defend his clay court singles title at next week's Sovran Bank/D.C. National Tennis Classic. He said yesterday he is withdrawing because of an ankle injury that has not healed in two months.

Noah, of France, who was to be the No. 1 seed in the tournament, injured his ankle during practice on May 19. He aggravated the injury in the French Open, where he withdrew in the round of 16.