They are like ancient warriors, these Detroit Pistons and Boston Celtics. Big, slow and cunning. They battle from memory as much as from muscle.

They have fought one another so many times, in so many important games, there are no surprises. They slam and bang and grind on one another, as they did Monday night, until someone finds the strength and the will to win.In Game 4 of their Eastern Conference semifinal, they were tied 53-all at halftime. Then Mark Aguirre played his best game in a Detroit uniform, leading the Pistons to a 104-97 win that tied the best-of-7 series at two games apiece.

Aguirre, whose previous best was 32 points since coming to Detroit in a 1989 deal for Adrian Dantley, scored 20 of his 34 points in the second half.

But there were many heroes:

- Joe Dumars and Dennis Rodman each played a full 48 minutes for Detroit. Dumars scored 24 points. Rodman, who was named NBA defensive player of the year earlier in the day, pulled down 18 rebounds.

- James Edwards got the Pistons off on the right foot, scoring their first 10 points in the game.

- Vinnie Johnson, starting for the injured Isiah Thomas, scored 10 of his 12 points in the second half.

- Kevin McHale, playing 37 minutes in a reserve role, scored 28 points for Boston, often keeping the Celtics in the game with flurries of points that frequently slowed up Detroit scoring runs.

- Robert Parrish scored 12 points and pulled down 10 rebounds, despite fouling out after playing only 23 minutes.

- Reggie Lewis scored 20 points for Boston.

"The key was that we did the job defensively," Detroit coach Chuck Daly said. "Those were two real good basketball teams going at it, old warriors who are very competitive. It was great basketball for any kind of purist who knows the game."

The Pistons are 5-0 in playoff games in which they have held opponents to under 100 points. They are 0-4 when allowing 100 points or more.

In the first three games against Boston, the Pistons shot just 37.2 percent and averaged 90.7 points. Detroit missed 28 of 85 free throws during those three games. But in Game 4 the Pistons shot 44.4 percent and sank 38 of 51 free throws.

And they did it without their floor leader, Thomas, who sat out the game with a sprained right foot.

"They are still a very dangerous team, whether he's in the lineup or not," Parrish said. "So that had nothing to do with it."

Indeed. The key was Detroit's 50-30 edge in rebounds, including a 15-3 advantage at the offensive end.

"It feels good when people say that we can't win without Isiah," Rodman said. "That's a lie. We've got a lot of people who can step up."

The series returns to Boston Garden for Game 5 Wednesday night. Game 6 will be played Friday night back at The Palace. A seventh game, if needed, will be played in Boston on Sunday.

The Pistons, attempting to become only the third team in history to win three consecutive NBA titles, have reached the Eastern Conference finals the past four years.

"Now it's all even up," Boston coach Chris Ford said. "I'm not satisfied because I wanted to be up 3-1."

And he had every reason to think the Celtics could go home with a two-game advantage after routing Detroit 115-83 in Game 3 on Saturday. The Pistons shot only 33.3 percent and missed 19 of 36 free throws in that game.

"You can't dwell on a loss like that in the playoffs," Edwards said. "The playoff series is too short to think about a loss like that. We have to put that behind us and come out and play like we know how to play."

Like ancient warriors.