Senators edge Maple Leafs 3-2
Anderson has a 7-1-1 record and .945 save percentage this month.
The Senators have climbed to fifth in the Eastern Conference and hold a nine-point advantage over the ninth-place Leafs.
Kyle Turris also scored for Ottawa, which hasn't dropped consecutive games in regulation since Nov. 9 and 11.
Matthew Lombardi and Joffrey Lupul scored for the Maple Leafs, who couldn't hold an early 2-0 lead.
The game featured two fights, including one between Leafs captain Dion Phaneuf and Nick Foligno in the second period that came six minutes after the Senators' forward had a low hit on Phaneuf.
Toronto got off to a fast start against the Senators, who were playing for the second consecutive night.
Lombardi beat Anderson with a shot through the legs at 6:51 of the first period, giving him his first goal in a 17-game span going back to Oct. 27.
Lupul extended that advantage less than 10 minutes later after taking a pass from Phil Kessel on a 2-on-1 break.
Ottawa had been outplayed to that point, but Alfredsson gave the Senators some life just before the intermission.
The captain took a pass from Milan Michalek and backhanded a shot over James Reimer with 7.5 seconds left in the period.
Spezza tied the score at 16:46 of the second period on a play that needed video review.
He reached his stick over Reimer and just got a piece of a shot that teammate Kaspars Daugavins had kicked toward the empty net.
However, the best performer of the period was Anderson, who stopped all 21 shots from the Leafs.
None of the saves were spectacular -- he was also fortunate to have Lupul hit the post -- but it was exactly what his team needed.
Turris capped the comeback when he raced in and beat Reimer with a high shot at 1:24. The center has 11 points in 15 games since being acquired in a trade from Phoenix.
The victory came at an important time as Ottawa has four more road games before hosting the All-Star game later this month. The Senators visit San Jose, Anaheim, Los Angeles and Phoenix before the break.
Notes: Andre Petersson and Mark Borowiecki sat out for the Senators. ... Nazem Kadri was a healthy scratch for Toronto. He had one assist in his past seven games. ... It was Reimer's first start since a Dec. 31 loss in Winnipeg. ... Alfredsson's goal was his 32nd in 73 career games against Toronto. ... The teams meet again Feb. 4 at Scotiabank Place.