As he did, Braydon Coburn flipped the puck out of the defensive zone. It fluttered and then checked up just inside the Flyers' offensive zone, like a Rory McIlroy pitching wedge.
Gustafsson, playing only because his coach had to go to Plan B, darted for the puck as Rangers goaltender Henrik Lundqvist had to scramble back to his net. It was such a funky hop that Lundqvist originally thought he could make a play on it.
On a night when the Flyers got all the bounces, Gustafsson slipped the puck through Lundqvist's five-hole to give the Flyers a commanding 3-0 lead on the way to a 5-2 win.
"It was a lot of fun when I saw the puck come down to me," Gustafsson said. "I think it took a fortunate bounce. I almost thought Lundqvist was going to get it, but luckily the puck went in."
When Nicklas Grossmann went down with a season-ending ankle injury in Game 4 - an ankle that was surgically repaired yesterday - Flyers coach Craig Berube initially went with veteran Hal Gill as a replacement for Game 5 of this series. The coach was hoping that Gill's 110 games of playoff experience would offset any rust accumulated by a 39-year-old defenseman who had played six games all year.
That didn't work. Gill was on the ice for two of the Rangers' goals in the 4-2 loss.
So Berube went back to his drawing board and pulled off Gustafsson, who played only 31 games this season. Gustafsson, a member of Sweden's Olympic taxi squad this year in case of injury, is 14 years younger than Gill.
"That was an important goal," Berube said, "but his game overall was good. He skated well, he was head's up all game."
Gustafsson was expected to be a regular part of the Flyers' defensive rotation, but he was unable to gain Berube's trust when the rookie coach took over and was a healthy scratch for most of the season.
There were times, he admits, when his confidence sagged. Given how this series has transpired, it's ironic who was there to pick him up.
"I have to credit Hal Gill a lot," Gustafsson said. "He's helped me out a lot this year when we were [scratched] together. He gave me pointers here and there and also kept my motivation up. He taught me to be a real pro: work hard in practice and when you get the chance, you're ready."
Gustafsson made his NHL debut in 2011 when Chris Pronger had an injured hand. In 2012, Gus was pulled off Peter Laviolette's bench as an injury replacement for Grossmann, and scored a goal in the series clincher against Pittsburgh.
A restricted free agent at season's end, Gustafsson now gets to play in a playoff Game 7 and another chance to impress the Flyers' brass.
Right place, right time.
"Obviously, I was a little disappointed I didn't get to play last game," he said. "[Berube] had his reasoning and I accepted that. When I was told that I was playing tonight, I couldn't tell you how excited I was. I just want to play my game and show everybody I can play."
On Twitter: @EdBarkowitz