The center missed the previous four games with a right-hand injury. He played 18:51, had four shots on goal and was minus-1.
"It was so fun to be back out there," Backstrom said. "It's where everyone wants to be. You want to be on the ice. It's just too bad we didn't get the win."
RELATED: [Complete Lightning vs. Capitals series coverage]
The best-of-7 series is tied 2-2 with Game 5 at Tampa Bay on Saturday (7:15 p.m. ET; NBC, CBC, TVAS).
Backstrom won six of nine face-offs.
"Yeah, surprised myself a little bit there, but I don't know, it's the playoffs, you've just got to grind," he said. "I mean, it felt good in the first couple of face-offs so I just kept it up."
Backstrom was injured when he blocked a shot in Game 5 of the second round against the Pittsburgh Penguins. The Capitals won three games without him before losing 4-2 in Game 3 on Tuesday.
"Obviously when you watch the team win, it's awesome," Backstrom said. "But, yeah, as a hockey player, you want to play. It feels nice to be back."
The morning skate Thursday was the first time he participated in line rushes or worked on the power play since the injury. He took part in an optional practice Wednesday.
Backstrom's 13 points (three goals, 10 assists) in the Stanley Cup Playoffs are fourth on the Capitals behind Evgeny Kuznetsov (21), Alex Ovechkin (20) and John Carlson (14). Backstrom had five points (one goal, four assists) in five games in the second round.
"I feel good. I feel really good," Backstrom said. "... If I didn't feel good, I wouldn't play. The doctors wouldn't let me play either."
NHL.com senior writer Dan Rosen contributed to this report.
