Substitute Struijk’s stoppage-time header cancelled out Danny Welbeck’s first-half opener in a 1-1 draw at Elland Road and crucially clinched Leeds the point needed to climb out of the bottom three with one game remaining.
Leeds leapfrogged Burnley, who still have a game in hand after losing at Tottenham earlier on Sunday, and will head to Brentford on the final day hoping to retain their top-flight status.
“We’re alive right now, regardless of the last day,” Marsch said. “We just have to fight for any point. Any point gets us a little bit closer and shifts a little bit of the momentum.
Speaking before Everton’s 3-2 defeat at home to Brentford, Marsch continued: “We know Burnley have a match in hand, we know Everton have two in hand with three left. We need some help and then we need to be ready next weekend to do whatever it takes.”
Against Brighton – one of this season’s success stories under Graham Potter, Leeds were second best in the first half and appeared to be heading closer to the trapdoor when Welbeck’s neat finish gave the visitors a 21st-minute lead.
But, roared on by another full house, Marsch’s side improved markedly after the break, and could have been level earlier had it not been for inspired Brighton goalkeeper Robert Sanchez.
Struijk’s far-post header in the second minute of added time was just the second goal Leeds have scored in five matches and raised the roof at Elland Road.
“It was important,” said Marsch, who insisted he did not hear a section of the home crowd singing “Sack the board” before Struijk’s last-gasp equaliser.
“Good for our fans to feel that, good for our team to have that experience and use that momentum going into the last match.”
Marsch admitted he sensed doubt among some of his players during the interval.
“I could still see the looks on their faces at half-time that we weren’t 100 per cent believing that we could do it,” he said.
“In the end they did that really well and they emptied their tanks and invested so much to get us that point, which could end up being a massive point for us.”
Brighton boss Potter admitted Leeds were worthy of it after forcing Sanchez into a second-half masterclass.
“I can’t sit here and say the point wasn’t fair,” Potter said. “We fought for everything, so did Leeds, which you’d expect.
“It was a hostile environment that we managed as well as we could, a great experience for our guys, so in the end I’m OK with everything.”
Spanish keeper Sanchez produced world-class saves in either half to deny Mateusz Klich twice and also Raphinha.
“He did and that’s why you have to say a point is fair,” Potter added. “It’s Rob’s first season with the crowds and he’ll get better and better.
“His quality is there for everybody to see. We saw different sides to his game today, he was tremendous.”