Right wing Ray Neufeld deflected in a shot from 10 feet with 9:08 left in the game to beat visiting Vancouver and give Hartford its third straight victory.
The Whalers, 4-1-1 and atop the Adams Division, went three games over the .500 mark for the first time since joining the NHL six years ago.
Mark Johnson, who collected two assists, helped set up the winning play by getting the puck to Risto Siltanen at the right point. Siltanen's 40-foot slapshot was redirected by Neufeld into the goal.
The loss dropped the Canucks to 1-5 and was their fifth straight defeat.
Hartford took a 2-0 lead on goals by Sylvain Turgeon and Bobby Crawford, the fourth of the season for each. Turgeon scored on the power play 90 seconds into the game, rebounding a shot by Johnson, and Crawford scored at 17:13 of the second period, completing a series of passes from Chris Kotsopoulos and Ron Francis.
The Canucks closed to 2-1 at 18:07 of that period on Moe Lemay's 40-foot rising shot. They drew even at 4:14 of the third period when Gary Lupul beat goalie Greg Millen from seven feet.
Millen, who made 18 saves, raised his season record to 3-0-1.