Chevrefils, who came into the game with a disappointing one goal, scored his second tally of the game on a power play at 13:38 of the third period, giving Bruins (8-5-1) a two-goal lead.
Maple Leafs (7-5-2) scored first, as Al MacNeil fired a slap shot past Sawchuk at 5:53 of the first period.
Cal Gardner tied the game with a power play marker at 18:46.
Chevrefils put Bruins ahead at 2:46 of the middle stanza, and after Ted Kennedy scored his first goal of the season two minutes later to tie the game, Fleming MacKell put Boston ahead to stay with a wrist shot at 9:08.
The only goal of the third period was Chevrefils' second of the game.
Bruins blocked seven Toronto shots in the third period, yet Maple Leafs still managed to get 37 shots on goal for the game, but Sawchuk was strong all night.
Bruins are 5-0-1 in their last six games as they take over the second spot in the standings, coveted because of the home ice advantage it provides in the semi-finals.
Both teams lost a defenseman due to injury: Dick Cherry (BOS) took a puck to the face and Hugh Bolton (TOR) suffered a serious leg injury of some sort.
1st Period
TOR- MacNeil (Armstrong, Sloan) 5:53
BOS- Gardner (Labine, Flaman) PPG 18:46
2nd Period
BOS- Chevrefils (Bionda) 2:41
TOR- Kennedy (Stewart, MacNeil) PPG 4:49
BOS- MacKell (Stanley, Flaman) 9:08
3rd Period
BOS- Chevrefils (MacKell, Bionda) PPG 13:38
SOG
BOS 10-6-10 = 26
TOR 8-16-13 = 37
PP: BOS 2-4; TOR 1-5
Goalies
BOS- Sawchuk
TOR- Chadwick
Sawchuk makes one of his 35 saves, this one against Sid Smith