Ryder's shootout goal capped an enthralling affair between the two Original Six rivals, the first of eight head-to-head matchups on tap again this season.
Sheldon Souray and former Leaf Mike Johnson scored in regulation for the Canadiens, who opened the season the previous night in a 5-4 shootout loss at Buffalo, another high-tempo and fast-paced affair.
Darcy Tucker and Matt Stajan scored for the Maple Leafs, who blew a 2-1 third-period lead, much to the disappointment of most the 19,353 fans at Air Canada Centre, although several hundred wore Habs jerseys.
David Aebischer stopped 36 shots in goal for Montreal while Andrew Raycroft stopped 31, both goalies outstanding on a night when the score should have been higher.
Both teams had power plays in overtime as a result of dubious penalties to Montreal's Sergei Samsonov and later Tucker. The Leafs had tremendous pressure on their 4-on-3 advantage, but Aebischer stood tall, making huge saves on blasts from Bryan McCabe, Tomas Kaberle and Mats Sundin.
The Habs opened the scoring 5:11 into an evenly played first period. Souray's blast from the point on a power play beat a screened Raycroft, who couldn't see a thing with Tomas Plekanec parked in front of him.
Tucker tied it at 9:28, one-timing a picture-perfect, cross-crease pass from Kyle Wellwood on a Leafs power play, the kind of play that requires soft hands and shows just why Leafs coach Paul Maurice may be a genius for starting Wellwood on the first line this season.
Stajan gave Toronto its first lead 4:38 into the second, a period dominated by the Leafs, sliding the puck under a sliding Garth Murray after Aebischer had made four straight stops at the end of a Toronto power play.
Johnson, who began his career in Toronto, tied it 2-2 at 6:47 of the third period, snapping a shot from the high slot that beat Raycroft stick side. The play began with centre Radek Bonk hitting Leafs defenceman Hal Gill behind the net and getting the puck out to Johnson, who netted his first in a Montreal uniform after coming over in a trade from Phoenix this summer.
Johnson had a chance to give his team the lead with 7:25 left in the third period, flipping a shot over the goal with an empty net staring at him after Raycroft first kicked out a save on Alexander Perezhogin from in-close.
Raycroft stole the show during a Montreal power play with less than six minutes left in the third period, a toe save on Michael Ryder followed moments later by a breathtaking sliding pad save on captain Saku Koivu.
Andrew Wozniewski's night lasted only 26 seconds, the Leafs defenceman suffering a shoulder injury on his very first shift and not returning to the game.
The hit of the night goes to Habs defenceman Mike Komisarek, who absolutely levelled Tucker with a clean but thunderous hit inside the Leafs zone in the second period.
Both clubs went 1-for-6 on the power play.
Notes: Defenceman Francis Bouillon, who was outstanding for Montreal last season, is out until later November at the earliest as he recovers from knee surgery ... Defenceman Mark Streit and tough guy Aaron Downey were healthy scratches ... Defencemen Carlo Colaiacovo (head), Staffan Kronwall (ankle), Brenden Bell (foot) and forward Nik Antropov (leg) were out again for Toronto while winger Aleksander Suglobov and defencemen Jay Harrison were healthy scratches ... The Leafs host the Florida Panthers on Monday night while the Habs are off until Wednesday at Philadelphia, where they complete their three-game road trip to open the season.