Colton Sceviour scored for the Panthers (10-13-2), who failed in their attempt for their first three-game winning streak of the season. Roberto Luongo made 30 saves.
Tierney scored to make it 2-1 at 7:13 when his sharp-angled backhand bounced off Luongo's back and crossed the goal line before defenseman Mike Matheson cleared the puck.
The goal was awarded after play was stopped for video review.
"I didn't really see it wholly," Tierney said. "I thought the angle I hit it off his back that it was going to go in. I thought I saw something cross the line. I'm glad we have instant replay and they can check that out."
Sceviour gave Florida a 1-0 lead with 1:49 left in the first period on his own rebound after Dell stopped his redirection from the front of the net.
Pavelski tied it 1-1 at 11:20 of the second period after Joe Thornton's pass from behind the net bounced off Panthers center Aleksander Barkov's skate and to the front of the net. Pavelski maneuvered his body out of the way before sliding the puck past Luongo.
The goal was upheld after Florida coach Bob Boughner challenged for goalie interference by Pavelski.
"Definitely a turning point in the game and also we hit the post on the power play in the second period," Boughner said. "That goes in, it's 2-0, it's different. Fine line. We didn't respond very well after they got that goal. We sat back and watched and stood around too much. Had a good third but couldn't have that goal we needed."
Dell, making his second consecutive start even though No. 1 goalie Martin Jones returned after a one-game absence because of an undisclosed injury, made 18 saves in the third period.
"The guys played really well," Dell said. "There were some huge shot blocks when we were [5-on-6] to preserve the win. They had a lot of shots, but we didn't give them a whole lot of chances on those shots."
