Brent Burns and Tomas Hertl had a goal and an assist each for the Sharks (35-22-6), who remain third in the Pacific division trailing the Anaheim Ducks and Los Angeles Kings. Martin Jones made 28 saves for San Jose.
Jake Virtanen and Sven Baertschi scored for the Canucks (24-27-12). It was Vancouver’s third straight loss and fall 10 points behind Minnesota and Colorado for the second Western wild card berth. Ryan Miller stopped 27 shots in the Canucks net.
It was the first of a home-and-home series between the two teams, who met on Sunday with the Sharks winning 4-1 at Rogers Arena. They play again on Saturday in San Jose and then twice more before the end of the month.
Marleau scored the go-ahead goal at 14:31 of the third as Sharks winger Joonas Donskoi skated up the boards before dishing it to Marleau for the smooth one-timer.
The Canucks came out with energy in the first period and were rewarded at 7:14 when Virtanen whipped a shot at Jones, then grabbed his own rebound and skated around the net before banking it in off Joe Pavelski's skate.
Vancouver made it 2-0 with a minute 30 seconds left in the first. With the Canucks buzzing in the Sharks zone, Dan Hamhuis fired a puck through traffic that Baertschi deflected in. Virtanen also assisted on the play, as Vancouver finished the opening period with a 15-7 lead in shots.
The Sharks showed more bite in the second and scored midway through the period when Burns's shot from the blue-line was tipped in by Hertl. The goal was reviewed because it looked as though Hertl's stick was high, but the call stood.
Daniel Sedin was called for high-sticking late in the second and the Sharks made Vancouver pay early in the third. Running point on the power play, Burns blasted the puck through the slot and beat Miller to even the game 2-2 at 43 seconds into the period.