By Steve Ginsburg

WASHINGTON, Aug 3 (Reuters) Third seed Lleyton Hewitt advanced to the third round of the Legg Mason Classic with a gritty 6-7 7-6 6-4 victory over an upset-minded Vincent Spadea in a two-hour, 32-minute slugfest.

In other matches involving seeds, number seven Dmitry Tursunov of Russia defeated Edgardo Massa 3-6 6-1 3-3 when the Argentinean retired with an injury to his right shoulder yesterday.

Also advancing was eighth seeded Andy Murray of Britain, playing his first match under the tutelage of new coach Brad Gilbert, who stopped Paraguay's Ramon Delgado 6-4 6-3.

Rnked 96th in the world, American Spadea had Hewitt on the ropes when he forged a 5-3 lead in the second-set tiebreaker, but the Australian won the next four points to force a decisive third set.

Spadea was left to rue a costly double fault that allowed Hewitt to get back on level terms at 5-5 in the breaker.

''That was probably the biggest point of the match for me,'' Spadea told reporters. ''I kind of went for it (on my second serve), I didn't want to play it tentatively.

''I can't really be discouraged about that, but at the same time, I didn't execute it.'' Hewitt broke the American's serve in the ninth game of the final set to take a 5-4 lead and held on to clinch his sixth career victory over Spadea in as many matches.

''He's a tough player to play sometimes because he's so flashy,'' the world number 12 Hewitsaid.

''I hit some good first serves out there, swingers out wide, and he's slashing on it the whole time. Some go out by five or six metres and others go for clean winners.'' ''It's awkward to play against a guy like that.'' GOOD SHOTS Hewitt appeared to break Spadea's spirit after winning the second-set tiebreaker and taking the opening game of the third set on the American's serve.

However, the American dug deep despite the oppressive heat and humidity to break Hewitt and level the match at 3-3.

''He was sort of moping around a little bit and I wasn't sure if he was struggling or not out there,'' Hewitt said. ''He was still coming up with some good shots.

''I thought I was sailing to the finish line and all of a sudden, I'm in a dogfight.'' While Hewitt prepares to face Germany's Denis Gremelmayr in the next round, Spadea was left to ponder what might have been ''I almost pulled through tonight,'' he said.

''If I had a little extra juice. I'm coming close to having a win against him. I just don't match up too well because my weapons aren't big enough to overpower him.'' REUTERS PM BS1204