"This team has grown a lot since early in the season," Cowgirl head coach Colin Carmichael said. "We played a really tough schedule early on and I think that prepared us to play in games like this."
OSU (9-5-6) advances to its fifth Big 12 Championship match in the last six years, where it will meet top-seeded West Virginia (15-3-2) on Sunday at 3:30 p.m.
Dike gave Oklahoma State an early lead, using her chest to deflect a corner kick into the far corner of the net in the 22nd minute. Sophomore Madison Mercado was credited with the assist, bending the corner from the near side to the far post, where she connected with the Cowgirl freshman.
"Basically, it was a set piece that I just got my chest on and got just enough of the ball," said Dike, who scored her second goal of the tournament. "There wasn't really anything planned, on a corner kick like that, we're just all trying to get to the ball."
The Oklahoma State freshman earned the corner for the Cowgirls, pressuring Tech's Jade Dapaah to unload the ball as she was heading towards the Red Raiders' net.
It was just the seventh goal allowed by Tech this season, and the first time it has allowed a first-half goal since Nov. 16 of last season in the NCAA Tournament loss to Florida State.
"I'm not really sure where the breakdown was on the play," Tech head coach Tom Stone said. "It was (set up by) a sloppy clearance by us, and they took advantage."
The Cowgirls survived a barrage of shots from Tech in the second half. The Red Raiders held a 15-7 advantage in the match, including 12-3 in the final 45 minutes of play. Tech's Hannah Devine and Alli Murphy each attempted three shots in a balanced Red Raider attack.
OSU's defensive wall, which consisted of three sophomores and a freshman, helped Ongaro earn her fourth shutout of the season and second against Tech after the teams played to a scoreless draw in their first meeting of the year.
The Red Raiders had several chances at the equalizer in the second half. In the 55th minute, Murphy fired a shot to the far post from outside the box, which Ongaro needed to make a sprawling save on, knocking the ball away with her hands.
Midway through the half, junior Jaelene Hinkle found Devine with a cross in the middle of the box, but Devine's shot in traffic was deflected away by a defender.
Later in the half, Caity Heap had a pair of open shots, but could not find the net, with her second a blast from the middle of the box with 10 minutes remaining that sailed past the goalkeeper but just wide of the near post.
Tech goalkeeper Victoria Esson made two saves and allowed her first goal since October 11, in the Red Raiders' 2-1 victory over Oklahoma.
"We gave up the early goal, but I was really quite happy with our response in the second half," Stone said. "We really put some pressure on them, but you have to credit their defense; they blocked shots, they blocked crosses and found a way to win, and that's why they'll be playing Sunday."
Tech (17-2-2) falls in the semifinal round of the Big 12 Championship for the second year in a row after TCU advanced on penalty kicks in 2012.