Dave Bolland and Johnny Oduya scored in the third period as Chicago rallied from a two-goal deficit to send Game 1 of the Stanley Cup Finals against Boston to overtime.
Chicago took its first penalty of the game at 5:51 of the third when Michael Frolik was called for a trip on Bruins captain Zdeno Chara, and the Boston power play went to work.
The Blackhawks had killed off 55-of-58 shorthanded situations in the playoffs coming into the game, but failed to stop this one as Patrice Bergeron gave the Bruins a 3-1 lead.
Milan Lucic held the puck along the right boards and sent a pass to the slot that got deflected, but it made its way to Tyler Seguin, who quickly fired it over to the left circle where Bergeron one-timed it home with a clink of iron at 6:09.
Chicago refused to give an inch from there, potting the next two goals.
The first one came off a Boston mistake as rookie defenseman Torey Krug tried to clear the puck out of his end through the middle and it was picked off by Andrew Shaw, who skated it in down the right wing. From the boards, he fired it over to the left side and Bolland one-timed it home for his first of the playoffs at the eight-minute mark.
Corey Crawford kept it a one-goal game with around 10 1/2 minutes left as he stopped Milan Lucic off a 2-on-1 and the Blackhawks rewarded his efforts.
Holding the puck at the right point, Oduya blasted a shot on net that was going wide, but it his off the back of the left skate of Andrew Ference and trickled past Rask to tie the game at 12:14.
Both sides had their chances to finish the game in regulation, but the goaltenders held their ground to force overtime.
Boston broke through at the 13:11 mark of the opening period. David Krejci went for the puck behind the net and shrugged off a hit from Niklas Hjalmarsson. Krejci then dished the disc to the left circle where Nathan Horton one-touched it to the slot, and Lucic one-timed the puck home for his fourth of the playoffs.
Rask stopped eight shots in the first period and made a stop just 30 seconds into the second period as Marian Hossa got a shot on net from the slot that saw Rask make a left pad save on and the play went the other way.
Lucic won a battle in the neutral zone along the left boards and got the puck to Krejci, who took the disc in down the left wing. From the top of the circle, Krejci fed it to the slot and Lucic one-timed it in off Crawford for his second of the game 51 seconds in.
Chicago got on the board just over two minutes later. Hossa stole the puck behind the net and skated to the left boards, before sending it to the circle where Brandon Saad one-timed it high into the net for his first career playoff goal.
The strike energized Chicago as the team took the play to Boston over the next several minutes, generating pressure in the visitors' end and sending several shots on Rask.
Jonathan Toews had an excellent chance with just over 13 minutes to play when he sent a shot on net from the slot, but Rask came up with the stop.
The first power play of the game went to Chicago when Horton was called for interference on Michal Handzus in front of the Chicago net at 12:23.
Just 43 seconds later, Boston was called for too many men on the ice to give Chicago 1:17 worth of a 5-on-3, but the Bruins penalty killers did their job and limited the Blackhawks to just one shot, a one-timer from Patrick Sharp at the left circle that Rask easily stopped.
Chicago was awarded another power play when Chara was called for high sticking with 7:07 to play, but again limited to the hosts to just one shot to maintain a one-goal lead.