DAYTON, Ohio (Ticker) -- Lionel Chalmers was in the right place at the right time for Xavier.
Chalmers' follow shot with 21 seconds left lifted the 14th-ranked Musketeers into sole possession of first place in the West division of the Atlantic 10 Conference with a 73-72 victory over Dayton.
Xavier (20-4, 11-1 A-10 West) stretched its winning streak to 11 games, thanks to a heady play by freshman guard Dedrick Finn and Chalmers' good fortune. The Musketeers moved one-half game ahead of Dayton (19-5, 11-2).
The Musketeers faced a 72-71 deficit and had trouble getting the ball to star forward David West as the shot clock winded down. Finn shot a long 3-pointer that misfired, but the 6-foot Chalmers scooped up the rebound and scored.
"I believe (Dayton's) Mark Jones bobbled it and I grabbed it and put it up strong," Chalmers said. "There's nothing better than to come out against a team like this and a crowd like this, and get the win."
It was the only basket for Xavier over the final 5:50.
The Flyers, who had a 13-game home winning streak stopped, had one last chance, but Ramod Marshall was forced into an airball by West with one second left. Xavier ran out the clock and celebrated its fifth straight victory over its state rival.
"Obviously, this is a disappointing loss," Dayton coach Oliver Purnell said. "We fought hard to get ourselves in position to win. I felt good that we got Ramod in the lane going to the basket for the shot at the end. He's made that shot for us so many times before."
West had another strong game with 27 points and eight rebounds to lead Xavier, which shot 46 percent (26-of-57). It was another dominating display by a player who had a 47-point, 18-rebound effort two weeks ago in an 85-77 victory over Dayton. West was forced to the outside and nailed three 3-pointers.
"He took what they gave him," Xavier coach Thad Matta said. "He stepped up and took the three. I thought he had a tremendous all-around game."
"This is a tough place to win," West said. "They haven't lost here all year and we came in determined."
Xavier's frontcourt players had their way with Dayton in addition to West. Starting center Anthony Myles collected 15 points and 15 rebounds and his backup, freshman Will Caudle, made all five shots for 10 points off the bench.
"It was a joy to see Will play as well as he did," Matta said. "He and Anthony are doing a good job of playing off of David."
West nailed a long 3-pointer at the buzzer to provide a 38-32 halftime lead. Keith Waleskowski's 3-pointer pulled Dayton within 42-41 with 17:33 to go.
Myles scored four straight points as Xavier matched its biggest lead at 65-58 with 5:50 remaining. The Flyers responded with a 10-2 burst and took its first lead of the second half at 67-66 on Frank Iguodala's steal and dunk with 2:20 left.
"Frank's defensive quickness spurt at the end helped us," Purnell said. "The steal and dunk gave us a big lift."
Dayton took its final lead on Brooks Hall's basket with 63 seconds to go that made 0t 72-71.
Waleskowski scored 18 points and Sean Finn fouled out with 17 and four blocks for Dayton. Jones and Marshall struggled from the perimeter, misfiring on 13-of-19 shots with 7-of-9 coming from beyond the arc.
"We played well, we battled all game but we missed a key rebound at the end and that's all it took," Marshall said.
The Musketeers enjoyed a 38-30 rebounding edge and scored 18 points off 13 offensive rebounds.