Alex Morgan scored in the 123rd minute against Canada at the 2012 Olympic semifinals. (Erik Williams-USA TODAY Sports)

This is a repost of the legendary 2012 Olympic semifinal match between the USWNT and Canada from Aug. 6, 2012. The Concacaf rivals tangle again in the Tokyo 2020 semifinals Monday at 4 a.m. ET.

By Michael Lewis

BigAppleSoccer.com Editor

MANCHESTER — Like two great prizefighters battling for the ultimate prize, the U.S. and Canada women’s soccer teams traded punches and counter punches in an Olympic women’s semifinal on Monday night.

In a game for the ages, Alex Morgan headed in the game-winning goal three minutes of stoppage time in extratime to life the U.S. to a 4-3 triumph and into the gold medal match on Thursday.

As the game slowly ticked toward the dreaded penalty kicks, second-half sub Heather O’Reilly sent a right-wing cross to Morgan, who headed the ball over goalkeeper Erin McLeod and into the net on a chilly summer night at Old Trafford.

The win sent the Americans into the gold medal match at Wembley in London on Thursday, while the Canadians will play in the bronze-medal match in Coventry the same day.

“I don’t know why we want to make things so dramatic, but we do,” U.S. forward Abby Wambach said.

The U.S. had enjoyed a 43-3-5 advantage over its Canadian rivals, but you would have never known that.

The game had so many heroes.

Canada striker Christine Sinclair sparked Canada with a rare Olympic hat-trick.

U.S. midfielder Megan Rapinoe had two goals — including an Olimpico goal, directly off a corner kick.

And Wambach converted the equalizer in regulation in the 80th minute.

Minutes before extratime, Wambach gave her team a pep talk.

“I know I’ve said this before,” she said. “But it really does just take one moment and one chance, one moment of brilliance for somebody to do something individually spectacular.”

That was left up to Morgan, whose goal powered the Americans to their fifth consecutive win.

“I’m still in shock thinking of what just happened,” she said. “It was a crazy battle. It was amazing.”

Added Rapinoe: “It’s a little trademark of our team. We came back three times today and showed great heart.”

The victory left the U.S. ecstatic, relieved and with a chance to capture its fourth gold medal in five tries — against Japan at Wembley Stadium on Thursday.

“We are unwilling to give up and that says a lot about who we are as a team,” Wambach said. “Even when Canada scored their third goal there was something in me that knew that we had more, that we could give more. This team has belief in itself, even when the going gets tough.”

The loss left the Canadians devastated, angry and in the bronze-medal game against France.

“We feel like we were robbed,” McLeod said.

After the U.S. dominated the opening 10 minutes, the Canadians finally found themselves and started to play on even terms.

In fact, they dominated the next 10 minutes and Christine Sinclair made the Americans pay as she lifted the Maple Leafs into a 1-0 lead in the 22nd minute. After Abby Wambach lost the ball at midfield, giving Canada the possession. Marie-Eve Nault started the scoring sequence with a quick pass to Melissa Tancredi flipped the ball to Sinclair, took one touch past defender Rachel Buehler and put a move on Kelley O’Hara before beating goalkeeper Hope Solo from 10 yards.

It was Sinclair’s 141st career goal.

The Canadians almost doubled their lead five minutes later when Sophie Schmidt headed a point-blank attempt from the left side that Solo caught at the near post.

The U.S. had awakened and had a couple of close encounters during a seven-minute span.

First, Morgan headed a Megan Rapinoe free kick just wide left in the 31st minute. Then Morgan found all sorts of room on the right flank, brought the ball close to the the goal line and sent a cross to Abby Wambach, who headed her eight-yard opportunity wide right of the net and keeper Erin McLeod.

The U.S. began the second half throwing everything they could at the Canadians, who withstood the early pressure.

On the left side, Morgan fed Wambach, whose chested the ball and then fired a volley over the bar and into the stands in the 50th minute.

Four minutes later, the Americans scored off straight off a Rapinoe corner kick — an Olimpico goal — in an Olympic game. Rapinoe sent a drive into the box than went through the legs of defender Lauren Sesselmann and into the net. The ball hit McLeod’s leg after it traveled over the line.

It was Rapinoe’s second goal of the tournament.

But Canada refused to wilt, taking the led in the 68th minute. This time Tancredi beat Christie Rampone on the left wing and launched a cross that Sinclair headed home past O’Hara for a 2-1 advantage. The goal put Sinclair into a tie with Wambach with 142 goals on the all-time list.

The Americans, however, equalized on a Rapinoe blast from 17 yards from just inside the area, a line drive that hit off the left post and into the net in the 70th minute.

Sinclair was still up to the task as she headed home her third goal of the match, this one off a corner kick from eight yards that left Solo hopping mad.

Then, it was the U.S.’s turn to equalize. McLeod was called for taking too long — more than allotted six seconds — to kick the ball from the penalty area and the ball was brought back for an indirect free kick at the top of the box. Rapinoe wound up taking a shot that hit the hand of Sesselmann and referee Christian Pedersen (Norway) called a hand ball. Wambach took the ensuing penalty kick and drilled it into the lower left corner for a 3-3 tie and her 143rd international goal.

It was the fifth consecutive match Wambach had scored at least one goal in this tournament.

McLeod said she had not been warned by the referee about holding the ball too long.  She said Pedersen claimed she had the ball for 10 seconds. “She obviously counted the time when I was on the ground with the ball,” she said.

Rapinoe blasted the ball into the defensive wall and off the arm of Marie-Eve Nault, resulting in a penalty.

“She [the referee] actually giggled and said nothing, Classy!” Sinclair said. “We feel cheated.”