Sundin scored twice and added an assist to lead the Maple Leafs to a 5-1 victory over the Boston Bruins on Monday night.
Toronto suffered a demoralizing loss on Saturday by blowing a late lead, but Sundin helped them leapfrog Boston in the standings. Monday's victory gives Toronto 42 points, one more than last place Boston in the Northeast Division.
The Maple Leafs are 18-17-6.
"We need to win hockey games right now. We can't wait for people to get back from injuries. There's no time for excuses," Sundin said. "We have to do better defensively as a whole group and I thought tonight was a step in the right direction. If we want to be a playoff team we need to improve there."
Zdeno Chara scored for the Bruins, netting a rebound at 4:51 of the first as he was being checked to the ice. Boston had won four of its last six games, but dropped the last two games of its four-game road trip.
"We had no energy, no legs. There's no excuse. Toronto outworked us in all areas," Boston coach Dave Lewis said. "We just looked like we were skating in sand."
Sundin tied it 1-1 at 8:09 of the first with a power-play goal from the side of the net that got past goalie Tim Thomas. He added his 18th of the season by skating up the ice and putting a hard slap shot past Thomas, giving Toronto a 4-1 lead at 2:00 of the third.
Sundin assisted on O'Neill's goal at 5:13 of the third.
"Mats is putting us on his back and it's fun to watch him play. It's a lot of fun to be around him," goalie Andrew Raycroft said.
Raycroft has struggled of late, but he looked good against his former team. He made 27 saves, including several impressive stops in the third.
Gill gave Toronto a 2-1 lead at 12:19 of the first by throwing the puck on net from the point.
Newbury made it 3-1 at 12:24 of the second with a weak shot from the point that beat Thomas. Chara and Toronto enforcer Wade Belak battled in front of the net and along the boards just before and after the goal.
Both received roughing penalties.
"He's a big strong man out there," Belak said of the 6-foot-9 Chara. "He was definitely tossing me around out there. I'll have to lift more weights."
Newbury joked that he'll tell his future kids that he scored on breakaway or penalty shot.
"It will be top corner," Newbury said.
- Toronto's Darcy Tucker returned after missing two games with an injured left foot. Boston's Paul Mara checked Tucker in the boards in the first period. Tucker stayed down for a while, but stayed in the game.