Mathis (17) was part of the New Zealand under-17 team that beat Colombia 3-1 in Wellington on Tuesday night.
Mathis, who grew up in Gore before moving to Auckland three years ago to progress in football, had not made it on to the paddock in the first two matches as New Zealand lost to both Canada and Denmark.
But in New Zealand's final game of the tournament in Wellington on Tuesday night, Mathis cooled her heels on the bench initially before coming on with five minutes left in the first half.
She had an eye-catching game, playing down the left flank, and looked threatening at times, as New Zealand, on the back of a Rosie White hat trick, won 3-1.
The victory was just the second win by any New Zealand side in a Fifa or Olympic tournament, after the under-17 male side defeated Poland 2-1 in 1999.
Mathis said conditions on Tuesday night were not easy.
"The wind was really really strong and it was raining all the time.
But to beat the Colombians was great as they are the South American champions and haven't been beaten for a long time," she said.
"I was happy with my game. I thought I played all right."
She said she did not play against Canada, as she was told by coach Paul Temple she did not have the height against a big Canadian side.
That she was playing at all was a tribute to her hard work, as she broke her left ankle just over two months ago.
"I just strapped it up and it held together well."
The team disbanded yesterday and Mathis said she would head back to school at Takapuna Grammar.
Mathis, who wants to play professionally in Europe, tipped Germany or Japan to win the tournament.
