After back-to-back shutouts, Martin Jones was beaten four times in Game 4 as the Blues beat the Sharks 6-3 to tie the series 2-2.
St. Louis scored twice in the first period and never lost control.
Troy Brouwer tallied a goal at 6:14 in the first and Jori Lehtera followed at 10:11.
Kyle Brodziak put two past Jones in the second period, at 6:09 and 10:11. At that point, Sharks coach Pete DeBoer put James Reimer in goal.
The Sharks finally got on the board early in the third on a Joe Pavelski marker. But the Blues answered back nearly three minutes later on a power play goal by Brouwer.
Chris Tierney added a goal three minutes later to make the score 5-2.
With 5:05 remaining in the game, DeBoer pulled his goalie and the Alex Pietrangelo scored an empty-netter at 15:39.
A minute later, Melker Karlsson got one by Blues goalie Jake Allen to cut the deficit to 6-3.
Allen, replacing Brian Elliott in net, made 31 saves in the win.
Game 5 is Monday in St. Louis. Puck drop is scheduled for 5pm PDT.