"He looked like he was very determined out there today," Billy Cunningham said Sunday after the Philadelphia 76ers stayed alive against the Boston Celtics in the NBA playoffs. The description could have applied equally to veteran small forward Julius Erving or rookie power forward Charles Barkley.

Starting the game in place of 33-year-old Bobby Jones ("Just a hunch, I felt we needed the young legs," said Cunningham), Barkley responded with 15 points, 20 rebounds, three steals and three assists in the 76ers' 115-104 victory in Game 4 of their NBA Eastern Conference final series against the Celtics. Boston has a 3-1 lead, with Game 5 Wednesday night at Boston Garden.

Erving, 35, had made only one of 10 shots from the field in Saturday's 105-94 loss. There were some questions about whether his legs, like the rest of his body, would be able to come back strong Sunday. They did, although his shooting, four of 21, still was atrocious, despite all that determination.

Part of Erving's problem in Saturday's game was the 76ers' over-reliance on guard Andrew Toney. He ended a prolonged shooting slump, but at a cost of ball movement and shot selection.

Erving suffered the most during Saturday's game, even to the point of being pulled by Cunningham on more than one occasion. "I just never felt like I was able to get into the flow," he said. "It seemed like I was always coming in or going out."

Sunday, the 76ers were at least able to establish that the Doctor was in.

"We all have days where it's not falling for us but you have to forget it and come out strong the next day. And that's what Doc did," said Boston forward Larry Bird. "It just shows you the kind of class athlete he is to bounce back with a good game."

Last Friday, Erving reacted with annoyance to reports that the 76ers were interested in acquiring forward Clark Kellogg from the Indiana Pacers, a move that would probably mean decreased playing time for him. Then, following Saturday's game, the normally gracious Erving was brief, almost taciturn, with the press.

"The most important thing for us is to stay together as a team," Erving said after Sunday's game. "I had no thoughts of dissension or of us not staying together. I didn't even see Billy until the pregame meeting, but I was determined to come out and play an all-around game."

The 14-year veteran added that if he had been "able to hit my jump shot, the game would have been a blowout." The 76ers were in control throughout the game because often, Erving's misses were being retrieved by Barkley, who also had something to prove.

Last Friday, the rookie from Auburn declared that if the 76ers didn't win Game 3, "We'll be on vacation in the Bahamas by the end of next week." That quote was posted on a blackboard in the Celtics' locker room before the game.

It was obvious the veterans had not counseled Barkley on the value of keeping a low profile, not that it would have mattered to the irrepressible 6-foot-6, 265-pounder.

Averaging a team-high 11.7 rebounds in the playoffs, Barkley also has no problem with the idea that a rookie is leading the way on a star-studded team. "Hey, age don't mean nothing, all we're doing is playing basketball," he said. "That's what it's about, all them being older than me means is that their parents started having babies before mine did."

Barkley also stood by his evaluation of the 76ers' problems. "I'm no fool," he said, "they're still in control."

A number of the Celtics were surprisingly loose after Sunday's loss, a game in which the defending champions pulled such bonehead plays as receiving a technical foul for playing with four players, and idly dribbling the basketball while the clock ran out ending the third quarter.

"We're up 3-1, you won't see any tears coming down from our faces," said Cedric Maxwell. "You better call a priest, because they're about ready for their last rites."

But Kevin McHale, usually one of the team's more boisterous players, was subdued. "I just think that they were ready, ripe on the vine and ready to be plucked but we let them off the hook," he said. "I guess they deserve some credit for fighting off a sweep and playing a good game but I think it was more a case of us letting it get away."

And given their reprieve, the 76ers felt that perhaps a corner had been turned. "I think we have a pretty good chance in Boston because neither team has played that great," Erving said. "In fact, I think they may be ready to be plucked."