The Blues had to adjust to the news of forward Dylan Holloway being taken from the bench on a stretcher late in the first period and then being taken to the hospital.
"Once we heard he was OK, we were kind of talking in the locker room that we're all obviously in the same boat emotionally right now and we've got a job to finish for him ad to get two points," Sundqvist said of Holloway. "Now after the game, we can start shifting all our focus to him."
Holloway was hit in the neck by a shot from Lightning forward Nick Paul that deflected off the stick of Kyrou at 17:32 of the first. The forward finished his shift, playing another 16 seconds, before skating to the bench.
Play was then halted during a stoppage with 1:11 remaining in the period, when Holloway was being attended to on the bench by the Blues' medical staff.
The teams were sent to their respective locker rooms, and the remainder of the period was finished at the start of the second period.
"It's one of those things you don't want to be a part of; I've been through one of them and thankfully he's OK," Blues captain Brayden Schenn said. "I'm not the guy to give updates, but we know he's doing OK. Just a freaky accident, freaky thing that happened. Glad that we got good news and he'll be fine."
Nikita Kucherov had two assists, and Andrei Vasilevskiy made 20 saves for the Lightning (7-6-0), who have lost three straight after winning three in a row.
"Score more goals than the other team and defend," Lightning coach Jon Cooper said when asked about winning the first game of the four-game trip, then losing three in a row.