Mackenzie MacEachern, Jaden Schwartz and Robert Thomas also scored for the Blues, who snapped a three-game skid. Jordan Binnington made 27 saves after getting pulled from his previous start against Toronto last Saturday when he allowed four goals on 11 shots.
Max Pacioretty and William Carrier had the goals for the Golden Knights, who lost for the third time in four games. Marc-Andre Fleury stopped 25 shots in his 820th career game, which tied Sean Burke for 14th on the NHL’s all-time list.
The Blues took control with two goals in a 39-second span late in the second period.
Schwartz gave the defending Stanley Cup champions a 3-2 lead with 5:07 left in the frame, ripping home a big rebound off a shot by Brayden Schenn. Thomas made it 4-2 moments later, beating Fleury short side on a shot that deflected off his arm.
MacEachern gave the Blues a 1-0 lead on a one-timer off Jacob de la Rose’s pass at the 4:52 mark of the first period.
Pacioretty tied it 25 seconds later, putting in his own rebound on a breakaway for his second goal in two games.
Carrier’s first goal in 14 games gave the Golden Knights a 2-1 lead with 7:32 left in the first. Carrier tucked home a rebound of Nate Schmidt’s shot.
Sundqvist tied the game for the Blues at 1:34 of the second, deflecting Alex Pietrangelo’s shot past Fleury for his ninth of the season.
NOTES: The Blues avoided their first four-game streak without a point since February 2018. Earlier this season, St. Louis lost four straight in October but earned points with two overtime losses in that span. … Vegas C Paul Stastny, who played for the Blues from 2014-18, has 30 points (11 goals, 19 assists) in 26 games against his former club. … St. Louis activated Sundqvist (lower body) and assigned LW Nathan Walker to San Antonio of the American Hockey League. … Vegas D Jon Merrill replaced D Nicolas Hague (illness) in the lineup.
Golden Knights: At the Dallas Stars on Saturday.
Blues: Host the Chicago Blackhawks on Saturday.