Frank Nazar had a goal and an assist, and Ryan Donato scored for the Blackhawks (28-36-14), who are 1-5-1 in their past seven games. Spencer Knight made 20 saves.
"We certainly pushed. They are a really good transition team. I thought we gave up too many grade A (chances) in the second. I think we have better in us," Chicago coach Jeff Blashill said.
Donato put the Blackhawks up 1-0 at 9:01 of the first period. Nazar one-timed a cross-ice pass from Connor Bedard in the left face-off circle and Donato cleaned up the rebound in front just one second after a power play expired. Bedard's assist was his 200th NHL point (75 goals, 125 assists).
The Sharks appeared to tie the game 1-1 at 2:02 of the second period on a goal by Michael Misa, but the goal was disallowed because it was determined Misa kicked the puck in.
Eklund did tie it 1-1 at 6:57. After intercepting a pass from Chicago defenseman Wyatt Kaiser at the Sharks' blue line, Eklund raced down the ice on a breakaway and put a wrist shot through the five-hole of Knight.
"Tried to stay on the puck on the defensive side there," Eklund said. "They made a play on the blue line, and I was just trying to go, and it went in."
Sherwood put San Jose up 2-1 at 14:55. Eklund fed a pass from below the goal line to Sherwood at the top of the right circle, where he dropped to one knee and buried a one-timer into the top left corner.
Smith pushed the lead to 3-1 at 3:28 of the third period. Macklin Celebrini sent the puck to Collin Graf at the left of the crease, and Graf then placed a behind-the-back backhanded pass to Smith in the slot, where he put a snap shot past Knight. The goal was Smith's 100th point in the NHL (41 goals, 59 assists).
"That was a great all-around play. Good forecheck, and then (Celebrini) made a play down to (Graf) and Graf made a great behind-the-back pass to me," Smith said.