STROUDSBURG, Pa. -- C.J. Oldham's tip-in with 1:20 remaining gave Gannon a 62-61 lead before four free throws iced a 66-64 victory for the Golden Knights against Mountain East Conference champion Charleston on Saturday night during the first round of the NCAA Division II Atlantic Regional hosted by East Stroudsburg.

Saturday's victory was Gannon's first in an NCAA tournament since the 2008-09 squad won the Atlantic Regional at the Hammermill Center. It also clinched the 25th 20-win campaign in school history, including each of the past two seasons.

Gannon will face the region's top seed and host school East Stroudsburg during Sunday's regional semifinals, beginning at 7:30 p.m. ET.

Gannon came through in several clutch situations during the final minutes of Saturday's first-round contest. Tied at 58, Girbran Smith drained a jumper with 2:55 remaining.

Charleston regained the lead at 61-60 with an Aleksandar Kesic free throw and Xavier Humphrey dunk. Oldham followed with the biggest tip of the season, tapping in a missed shot to give the Golden Knights the lead back at 62-61 with 1:20 to play.

Gannon regain possession with a one-point lead and milked the shot clock down, before missing a shot with 14 seconds remaining. Charleston grabbed the rebound and raced down court. But Denzel Douglas missed a contested jumper from the baseline. The Golden Knights corralled the rebound and were immediately fouled.

Adam Blazek and A'Darius Porter went 2-for-2 from the line during the final nine seconds to ice the victory. A half-court 3-pointer by UC accounted for the final 66-64 score.

Gannon led the entire first half. The Golden Knights held the Golden Eagles scoreless for the first six minutes and 40 seconds while racing out to a 14-0 lead. Raphell Thomas-Edwards led four different scorers during the opening run with six points. Charleston clawed within 26-24 on Douglas' three-pointer at the 4:02 mark, but was never able to get over the hump in the first half. Gannon eventually went to the break with a 33-30 advantage.

The second half turned into a back-and-forth affair that featured eight lead changes and seven ties. Jabs Newby opened the final stanza with his second 3-pointer of the season, but Charleston followed with eight consecutive points to assume its first lead of the evening.

A 50-45 Charleston advantage midway through the second half was the biggest lead by either team during the final 19 minutes and 21 seconds. Smith hit a jumper and then a 3-pointer on the fast break to forge a 50-50 deadlock with 8:13 to play.

Smith tied a career-high with a team-high 18 points, going 7 of 14 from the field and 2 of 3 from long range. Porter recorded his fifth double-double with 12 points and 11 rebounds. Thomas-Edwards added 14 markers.

Gannon shot 44.2 percent (23-for-52) from the field, 25 percent (3-for-12) from 3-point range and 89.5 percent (17-for-19) from the free-throw line.

Humphrey led all scorers with 19 points in 40 minutes for the Golden Eagles. Fred Simpson followed with 12 points. Kesic and Douglas finished with 11 points each.

Charleston shot 42 percent (21-for-50) from the floor, 46.7 percent (7-for-15) from behind the arc and 71.4 percent (15-for-21) from the charity stripe.

Gannon improved to 20-9 with its 14th victory in the past 16 games. Charleston's season came to an end with a 21-9 mark.