Maryland learned three hours before its tipoff against Princeton that starting guard Lea Bartelme had torn her ACL and would miss the rest of the season. The loss left the Terps suddenly thin at point guard, forcing freshman Addi Mack into her first career start.

Mack was more than prepared, scoring 15 points in No. 9 Maryland’s 84-68 win against Princeton on Sunday afternoon at Xfinity Center.

Coach Brenda Frese brought the freshman in for her scoring talent, which has been on full display in the Terps’ non-conference slate. Mack led Maryland in scoring in its previous two matchups with 23 and 15 points, respectively.

But Frese clearly trusted Bartelme to run the offense. She took on a heavy load as a starter, averaging 23 minutes in her first three games. Mack, a more traditional scorer, will have to adjust to playing in a more facilitating role.

“I know that everyone here has my back and they trust me to, you know, step into that role as well,” Mack said. “I’m just really excited to just keep building off of it with the team.”

Mack finished with three assists and just one turnover in her first start as point guard — a positive sign after Maryland turned it over 22 times against Towson on Thursday.

[Kaylene Smikle returns in Maryland women’s basketball’s 88-70 win over Towson]

The Terps had just 19 assists to 22 turnovers on Thursday against Towson. Frese said her team would have to take “much better care of the basketball” to match up with Princeton’s upperclassmen-heavy roster.

Instead, Maryland still turned it over 16 times against the Tigers. After turning it over just once in the first quarter, it committed eight turnovers in the second frame. The Terps’ offense stalled out in the second period, getting outscored 20-8 and not scoring in the final 3:43 of the half. The Terps shot just 36 percent from the field in the first half.

“I thought fatigue definitely played a part,” Frese said about the second quarter. “We looked like we had never broken a press.”

It was the third consecutive game it finished with a non-positive assist-to-turnover ratio. Turnovers remain a concern, but some of that can be attributed to starting shuffling lineups.

The Terps just can’t seem to avoid injury trouble, though. Just eight minutes after last season’s leading scorer Kaylene Smikle returned to the court for the first time Thursday, Bartelme was helped off the court after landing on her knee.

[Maryland women’s basketball mailbag: What can we expect from the Terps this season?]

Then Sunday, Terps fans went silent when Mack took a scary fall under the basket. The freshman quickly returned to finish the game.

She helped engineer a strong third quarter, as Maryland took control of the game in the frame. Smikle scored eight points off free throws, the offense shot 80 percent from the field and made all three of its triples. Oluchi Okananwa scored a team-high 20 points on 9-of-13 shooting.

While not ranked, Princeton is Maryland’s first opponent of the season that received votes for the AP Top 25 poll. And despite the injury scares, the Terps are likely to emerge from the non-conference slate with two quality wins over Georgetown and the Tigers.

“This is going to be impactful for us when you talk about the future and why we play games like this within our scheduling,” Frese said. “Princeton is a really really good team.”