The American captain poked home a Megan Rapinoe corner kick just before halftime Tuesday as the United States downed Nigeria 1-0 to clinch top spot in Group D.
Wambach had blamed the plastic playing surface for her team's lack of goals through two games at the tournament after an uninspiring 0-0 tie with Sweden on Friday that saw the 35-year-old miss two golden opportunities.
She didn't have a problem converting on this night, but also wasn't about to back down from her comments.
"Scoring goals is not that easy. I'm not making any excuses," said Wambach. "I need to finish chances that are handed to me ... but that being said, the turf does make the ball bounce differently. You think differently about the game and that's just the reality."
Wambach was involved in a lawsuit by a group of international players prior to the World Cup over staging the event on turf, arguing the men's tournament has always been played on grass. The suit was eventually dropped, but Wambach has remained vocal and said the fact that her comments have made waves is a positive.
"It's awesome that we're talking about women's football," she said. "It's awesome that we're having some of these discussions. It's awesome that we're analysing and hyper-dissecting things that we all say. For me, that means there's growth."
The Americans wound up topping Group D — the so-called "Group of Death" because the U.S., Sweden and Australia are all ranked in the top-10 — with seven points and will play their match in the round of 16 in Edmonton on Monday.
Australia secured the second spot after tying Sweden 1-1 in Edmonton. The Australians wound up with five points, while the Swedes picked up their third straight draw to finish third with three points. Nigeria, meanwhile, completed its World Cup at the bottom of the group with a tie and two losses.
Wambach started her second game of the tournament alongside fellow striker Alex Morgan, leading the charge for an American side that had a number of chances before and after the breakthrough.
"(Wambach) just embodies a lot of the spirit of this team," said U.S. head coach Jill Ellis. "Her leadership is tremendous, her spirit is fantastic.
"I just know Abby. I know in big moments she'll deliver."
But despite the win, being more clinical in front of the goal will be a focus for the Americans as they move into the knockout stage.
"It comes down to focus in the box," said Ellis. "I would be concerned if we weren't getting opportunities."
Those opportunities included a Julie Johnston effort that was ruled offside, while Wambach saw a header go wide in the 18th.
Nigeria had a great chance to open the scoring in the 25th minute when Asisat Oshoala got on the end of a perfectly weighted pass behind the U.S defence, but Johnston recovered just in time to block her shot.
Morgan, who is being brought back slowly from injury and was making her first start, had chances to double the American lead in both the 48th and 62nd minutes, but was twice thwarted by Nigerian goalkeeper Precious Dede.
Nigeria had a player sent off in the 68th minute and the U.S. steered the game home from there, content with a 1-0 scoreline that ensured top spot in the group.
B.C. Place Stadium could have been mistaken for American territory during the match as thousands of fans draped in red, white and blue roared with approval every time one of their players touched the ball. Attendance was officially announced at 52,193.
"I thought the crowd was amazing," said Ellis. "I think that had a big part to do with our energy tonight."
Note: American striker Sidney Leroux came on as a substitute in the second half. Leroux was born in nearby Surrey, B.C., but chose to play for the U.S. instead of Canada and was greeted with some boos from the Canadian fans in attendance.
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