Smith, who also scored twice in a 4-3 loss to the Vegas Golden Knights on Saturday, has five goals in his past three games.
Tyler Toffoli had two goals and two assists, and Macklin Celebrini had three primary assists for the Sharks (13-11-3), who have alternated wins and losses in their past seven games (4-3-0). Yaroslav Askarov made 31 saves.
Lawson Crouse scored twice for the Mammoth (12-12-3), who have lost four straight. Karel Vejmelka allowed three goals on nine shots before being replaced in the first period by Vitek Vanecek, who made 19 saves.
Toffoli put the Sharks up 1-0 at 4:41 of the first period. Smith stole a pass from Mikhail Sergachev behind the net and passed out front to Toffoli, who beat Vejmelka over his glove with a shot from the high slot.
Pavol Regenda, who was making his season debut, pushed the lead to 2-0 with a power-play goal at 7:58 when Philipp Kurashev’s one-timer from the right circle deflected in off his left skate.
Crouse cut the lead to 2-1 at 9:06. Michael Carcone skated down the right wing on a rush before stopping and passing across the crease to Crouse for a tap-in at the back post.
Toffoli scored his second of the period to make it 3-1 at 12:59. Celebrini won a face-off in the right circle over to Toffoli, who quickly swept a shot five-hole on Vejmelka, who was pulled following the goal.
JJ Peterka made it 3-2 at 16:00 of the first. He skated into a cross-ice pass from Nate Schmidt and roofed a shot from the bottom of the left circle over Askarov’s shoulder.
Smith responded for the Sharks to make it 4-2 at 6:16 of the second period. He took a drop pass from Celebrini just inside the right point, toe-dragged around Schmidt at the top of the circle, and then made another move around Brandon Tanev before scoring five-hole from the hash marks.
Adam Gaudette extended the lead to 5-2 at 7:25. William Eklund forced a turnover by Barrett Hayton and got the puck up to Gaudette, who scored with backhand past Vanecek’s glove.
Smith scored his second of the period at 9:09 to make it 6-2. He took a pass from Toffoli on a rush and used another toe-drag on Sergachev to create space before scoring low glove side from the high slot.
Crouse scored a short-handed goal at 6:30 of the third period, tipping in a return pass from Sergachev to make it 6-3.
Smith scores 2 more, Sharks cruise past Mammoth
