Giroux made it 2-0 at 12:15 with a redirection that went between the legs of Golden Knights defenseman Brayden McNabb and then through Hill’s five-hole.
Nicolas Roy cut it to 2-1 at 17:23, and Nicolas Hague tied it 2-2 21 seconds later when he threw the puck toward the net and it went in off the skate of Senators defenseman Jake Sanderson at 17:44.
Batherson then put Ottawa back in front 3-2 at 18:34 with a shot from the high slot, but Barbashev tied it 3-3 at 6:40 of the second period by tipping a Pietrangelo shot.
Gaudette’s second goal of the game gave the Senators a 4-3 lead on the power play at 17:44. He scored with a wrist shot to the glove side from the top of the slot.
“It was a wake-up call for us. We didn’t play our best today,” Barbashev said. “We let them run around 50 minutes of the game. We all know we have to be better.”
NOTES: Giroux has seven points (three goals, four assists) in a five-game point streak. … Senators forward Brady Tkachuk had his season-opening six-game point streak and three-game goal streak end. … Reinhardt was playing his second NHL game and first since April 7, 2022. … Ottawa forward Michael Amadio was minus-2 in 14:22 of ice time in his first game against Vegas since signing a three-year, $7.8 million contract ($2.6 million average annual value) with the Senators on July 1. He played the past three seasons with the Golden Knights. … Pietrangelo had three assists for the second consecutive game, having done it in a 6-1 win against the Los Angeles Kings on Tuesday.