The squads needed overtime to decide the matter, but in the end, Presentation prevailed 2-1. Gastelum's first goal tied the game and her second, five minutes into overtime, gave the Saints their first victory of the season.
Getting the chance to play with a full team was a plus for the hosts, said PC coach Jacob Plocher.
"It was exciting," said Plocher. "It was the first time were able to get 11 girls on the field."
The visitors held a 1-0 lead at the intermission, with Laura Ekeren scoring on an assist from Breanne Kuehler. Plocher let his team know it had plenty of time to regroup.
"At halftime, I told them there's not too much they can do (about the goal), but they have 45 minutes to get it back together."
Saints goalkeeper Samantha Surrell, who stopped 15 shots on the day, held the Lancers scoreless the rest of the way.
Six minutes into the second half, Gastelum scored the tying goal, with an assist from Haley Hobbs.
"We did a good job of moving the ball well," Plocher said. "They were playing their back line high and we got over the top of them. Bree played the ball where she needed to."
The Saints came in ready to play and were thrilled to get their first victory of the season, Plocher said.
"We knew it would be a battle. We were motivated and determined to put together a good performance," said the PC coach. "It was definitely worth all the hard work they put in."
Mount Marty, which fell to 0-4-1 on the season, had 31 shots in the game, compared to 14 for the hosts. Presentation, now 1-4 on the year, have a long break before their next action. On Sept. 26, PC will host Dakota Wesleyan at Saints Field at 5 p.m.
Presentation 2, Mount Marty 1 (OT)
First Half: 1, Mount Marty, Laura Ekeren (Breanne Kuehler), 39:05.
Second Half: 2, Presentation, Bree Gastelum (Haley Hobbs), 51:45.
Overtime: 3, Presentation, Gastelum, unassisted, 95:45.
Goalies: Mount Marty, Courtney True (8 saves); Presentation, Samantha Surrell (15 saves).