Mikkel Boedker scored his second straight overtime game-winner to give visiting Phoenix a commanding 3-1 edge in their Western Conference quarterfinal series against Chicago.
Boedker, who won Game 3 in overtime, outraced Chicago's defense and appeared to loose control of the puck but it slid underneath Blackhawks goaltender Corey Crawford for the victory at 2:15 of the extra session.
Shane Doan and Taylor Pyatt also scored for the Coyotes, who blew a two-goal lead in the final 10 minutes before Boedker's heroics.
Mike Smith turned aside 30 shots for Phoenix, which can wrap up the series at home in Saturday's Game 5.
It marked only the second time in league history that a series has opened with four straight overtime games. The other was the 1951 Stanley Cup Finals between Montreal and Toronto.
The Coyotes seemingly took command of the game -- and the series -- when Doan and Pyatt scored 44 seconds apart in the third period for a 2-0 lead with just over 12 minutes to play.
The Blackhawks refused to wilt and cut the deficit in half less than three minutes later on Brendan Morrison's tally, his first point in 12 games with the team since he was acquired from Calgary.
Chicago swarmed the Coyotes with relentless pressure and finally got the equalizer when Michael Frolik poked a rebound past Smith with only 1:26 left in regulation.
Crawford had 16 saves for Chicago, which came back from a 3-0 series deficit vs. Vancouver last season before losing in Game 7.