Sumner was coming into his own before going down with a head injury in a scary collision less than three minutes into a 95-64 loss at then-No. 16 Villanova on Dec. 31. The redshirt freshman had reached double-digit points in six of his previous seven games, including 21 against Wake Forest on Dec. 22.
With the playmaker sidelined, Davis has totaled 30 points and nine assists to help Xavier bounce back with an 88-69 home win over then-No. 9 Butler on Jan. 2 and a 74-66 win at St. John's on Wednesday.
He sank all nine of his free throws and scored 16 of his team-high 19 points over the final nine minutes versus the Red Storm. Davis leads the nation with a 95.2 free-throw percentage after making 23 in a row.
Now he'll try to keep holding things down in his new role after coach Chris Mack told reporters Sumner probably won't be ready to return as Xavier (14-1, 2-1) seeks its ninth consecutive win to open the season at the Cintas Center after starting 12-0 there in 2013-14 and 11-0 last season.
"(Davis has) been a point guard over the last couple of games," Mack said. "He's played the 2 primarily all year. He's trying to get players organized in the right spots. He's able to keep a calm and cool head, get to the rim and hit a floater, come up with a loose ball, get fouled and make his free throws."
Davis finished with 25 points while going 8 for 10 from the stripe and added eight rebounds as the Musketeers salvaged a split of last season's series with an 89-76 home win over DePaul on Jan. 24. He also scored 14 while hitting all nine of his foul shots in a 71-68 loss at Allstate Arena earlier that month.
Trevon Bluiett proved a difficult matchup for the Demons, totaling 40 points on 56.0 percent shooting with 16 rebounds in the two meetings. The sophomore guard, who averages a team-high 14.5 points, contributed 18 while sinking 9 of 11 from the free-throw line Wednesday.
DePaul seeks its first Big East victory after losing four in a row and seven of its past eight games. The squad hasn't dropped its first five conference contests since an 0-12 start during the 2010-11 season.
Billy Garrett Jr. had 16 points as the Demons (6-10, 0-4) shot 35.7 percent in Saturday's 74-63 loss at Georgetown. Garrett, who surpassed 1,000 career points, has averaged 17.2 over his last five games.
The junior guard averaged 16.7 points and 6.0 assists in three career games versus Xavier before finishing with six and six while battling foul trouble in the most recent meeting.
The Musketeers rank eighth nationally with a plus-11.2 rebounding margin, though the Demons have done better on the glass in conference games with a plus-5.5 mark compared to Xavier's 4.3.
Xavier has won three of the four matchups since joining the Big East in 2013-14.