The Tulane baseball team’s highly anticipated debut went from a nightmare to exultation with one swing of the bat.

After the Green Wave blew a two-run, two-out ninth-inning lead and fell behind by three runs in the 10th, designated hitter Jeremy Montalbano blasted a three-run homer to deep left-center for a dramatic 6-5 victory on Friday Night at Turchin Stadium.

The Wave, which rallied for some unlikely wins in its final at-bat several times last year en route to its first NCAA regional appearance since 2008, topped itself this time in front of 3,058 fans.

The largest crowd for a home opener since 2011 witnessed an incredible finish. After two walks and a single loaded the bases with no outs in 10th, Montalbano got all of an 0-1 pitch from Nick Blackburn.

“He threw it right into my wheelhouse,” Montalbano said. “I got good wood on it.”

Forgive him for forgetting he was using an aluminum bat. Montalbano, a Texas transfer who had not played since 2014, made up for lost time right away.

“It felt amazing,” he said. “I don’t think you can draw up a better story when you don’t play for a year and a half.”

The Wave was so close to winning about 45 minutes earlier after starting pitcher Corey Merrill went six scoreless innings and allowed only three hits.

But reliever J.P. France gave up two doubles in the ninth as Illinois cut the deficit in half. Patrick Duester replaced him with two outs after the second double, and France immediately surrendered another double down the right-field line.

Although Duester got out of a bases-loaded jam to stop the damage, he walked the bases loaded in the 10th before pinch hitter Mark Skonieczny ripped a two-RBI double to the right-field wall off Trevor Simms. The Illini, who had the best winning percentage in college baseball last year, tacked on another run and appeared headed for a stunning victory.

The Wave, and Montalbano, had another idea.

“I knew I got it good, but I wasn’t 100 percent (sure it would go out) because I hit it to the deepest part of the field,” Montalbano said. “It was amazing.”

Teammate Jordan Gross smeared him with shaving cream during a postgame interview.

“That was as good as it gets,” Pierce said. “We just hung in there. It was tough, but we just had some good quality at-bats to put ourselves in position. Jeremy gets a good hanging baseball, and he’s already paying dividends.”

The news turned out even better when Pierce said All-America candidate shortstop Stephen Alemais, who left in the top of the 10th with an injury, had only suffered cramps in both hamstrings and would be fine.

The Wave appeared to be wasting another stellar effort from Merrill, who went winless in 2014 with a 3.60 earned run average and 5-6 in 2015 with a 2.12 ERA — his first season as a Friday starter.

After Montalbano’s homer, Merrill was in just as celebratory a mood as the rest of the team.

“I don’t care about the win-loss record,” he said. “I only care about the win. I’m taking it.”

Tulane, which scored both of its runs without the benefit of an RBI, blew numerous chances to extend the lead while striking out 15 times.

Simms (1-0) took the victory despite giving up three hits in relief of Duester.

Jesuit product Emerson Gibbs will pitch for Tulane Saturday in a 4 p.m. start.