Starting out sluggish in the first half, the Friars (18-1, 5-0) used a 15-0 run in the third quarter to put away East Suburban Catholic Conference foe Bishop McNamara 61-38 at the Fieldhouse on Thursday night.
Fenwick, which trailed 9-8 after one period, was led by Devereaux Peters' 17 points. Samantha Woods and Brittanny Johnson each score 12 apiece for the Friars.
"He was pretty upset and gave us a good talking to at halftime," said Johnson of Fenwick head coach Dave Power. "We had to execute the way we are capable, and we did that in the second half."
Fenwick's height advantage was prominent on the defensive side of the ball, with Peters swatting four shots in the first half. On offense, the mismatch didn't play out the same until the third period.
"Our defense was consistent the entire game," said Power. "We just needed to light a fire under the offense. Luckily, we finally got things going in the second half."
Fenwick got its first loss out of the way on Jan. 4, when fifth-ranked Sandburg downed the Friars 55-40 in the Sweet 16 tournament.
"We shot poorly in that game, and I didn't prepare the team for Sandburg," said Power. "We were concentrating things on conference opponents."
The loss pushed the Friars down from a No. 1 ranking in the state to No. 5.
Fenwick upped its overall record to 19-1 with a 58-41 non-conference victory over Harlan in the City-Suburban Shootout at the DePaul University Athletic Center on Saturday.
The team is scheduled to begin the McDonald's Shootout at Willowbrook this weekend.