Hasek, injured on a go-ahead goal by defenseman Bret Hedican with 33 seconds left, will be evaluated by team doctors in Buffalo.
Sanderson took a pass from Curtis Brown and fired the puck past Florida goaltender Trevor Kidd for his fourth career overtime goal and first for the Sabres. His last OT goal came against Buffalo in February 1996, when Sanderson played for Hartford.
Brown drew Panthers defenseman Bret Hedican toward him on the two-on-one break and slid the puck to Sanderson. "He made a great shot low," said Brown, whose team is off to one of its worst starts.
"This was huge," Brown said. "We needed this one badly. We hadn't been getting many breaks, but we hadn't been working very hard, either."
Stu Barnes scored the tying goal with 18 seconds left in regulation, knocking in a loose puck during a scramble in front of the Florida net with the Buffalo goaltender pulled for an extra skater.
"Everybody crashed the net and I just took a whack at it," Barnes said.
Barnes' goal came just 15 seconds after Hedican ripped a slap shot past Hasek to give Panthers a 2-1 lead.
"We would have liked to have snuck out of here with one," Kidd said, "but it wasn't to be."
Hasek was injured on Hedican's 45-foot slap shot, which rattled in off the left post. The goaltender did a split while trying to make the save and was down for several minutes before being assisted to the bench.
"I didn't see the puck coming," Hasek said. "I knew the guy was shooting from the top of the circles. Somebody blocked my view and I saw the puck at the last moment. I tried to stop it with my right pad, and I felt my groin pull or whatever I did."
Hasek was replaced by Martin Biron, who made four saves in overtime.
"You don't see this kind of game too often," Peca said. "Of course, you don't want to be in a situation where you have to score two goals in 33 seconds. But this was our best game of the year, by far."
Hasek has struggled throughout the season and even looked shaky in Wednesday's 4-3 victory over the Tampa Bay Lightning, his first win of the season, in which he allowed three goals on 18 shots.
The Panthers didn't make Hasek work hard this time until the third, when the Sabres were outshot 12-11.
"The first two periods we didn't do too much," Florida coach Terry Murray said.
Buffalo (3-6-2) outshot Florida (6-4-1) 20-9 through two periods and the Panthers managed only three shots in the first, tying their season low for shots in a period.
"We didn't have a great night," said Panthers forward Scott Mellanby, whose team is one game into a five-game road trip. "There's crazy finishes all the time. We just have to forget about it and move on."
Whitney tied it at 7:06 with his fifth goal of the season.
The Sabres were in the middle of a defensive line change on the play and their forwards lost the puck in the neutral zone. A pass from former Sabres defenseman Mike Wilson sent Whitney in alone through the left circle, and the soft wrist shot fluttered over Hasek's glove.
Hasek stuffed Pavel Bure's wraparound with a minute left in the second.
Kidd, who had allowed 19 goals in six games against Buffalo, posting a 1-4 record and a 3.29 goals-against average, made two big saves on a Buffalo power play early in the third. First he got a pad on Zhitnik's shot from the point and stopped Jason Woolley on the rebound. He also turned back Satan with 1:13 left.
The Sabres survived 1:27 of a power play midway through the third, including 8 seconds of a five-on-three. Hasek made four saves on the power play, including a stop on Svehla on a point-blank shot.
Florida's Peter Worrell strained knee ligaments in the first period and will be evaluated Saturday.
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