Two first period goals from Colin Wilson either side of Viktor Stalberg’s strike put the Predators firmly in control in the first match of the best-of-seven series.
But the Blackhawks, who had closed their regular season with four consecutive losses, hit back in the next period as goals from Niklas Hjalmarsson, Patrick Sharp and Jonathan Toews levelled things up before Keith struck to give his side a 4-3 victory.
Kris Russell scored with just 30 seconds remaining as the Calgary Flames edged to a 2-1 victory over Canadian rivals the Vancouver Canucks.
Bo Harvat put the Canucks ahead but David Jones levelled before Russell’s goal in the final minute helped the Flames go 1-0 ahead in their series.
In the Eastern Conference, Brian Flynn’s tie-breaking goal lifted the Montral Canadiens to a 4-3 victory over the Ottawa Senators.
Torrey Mitchell and Tomas Plekanec struck for the Canadiens after Milan Michalek had opened the scoring for the Senators, who levelled things up following Kyle Turris’ penalty goal.
Lars Eller’s effort was cancelled out by Mika Zibanejad but Flynn struck with just under three minutes remaining to clinch an important win for the Canadiens.
Brock Nelson bookended the scoring as the New York Islanders claimed a 4-1 victory over the Washington Capitals, who had equalised through Marcus Johansson in the first period.
Ryan Strome and Josh Bailey restored the Islanders’ advantage before Nelson made sure of the win in the third period.