MILWAUKEE -- Butler guard Avery Woodson spent much of the Bulldogs' allowed practice time Wednesday bundled up in a cold-weather parka as temperatures in Milwaukee hovered around the freezing mark.

But Thursday, when fifth-seeded Butler faced No. 13 Winthrop in an NCAA Tournament South Regional first-round game at the Bradley Center, Woodson heated up quickly.

The 6-foot-2 senior knocked down six 3-pointers, including five in the opening half, and finished with 18 points as the Bulldogs cruised to a 76-64 victory over the Eagles at the Bradley Center.

"They know where I'm from," said Johnson, a native of Wayesboro, Miss. "I'm not used to this cold weather. But the first half, that was just the end result of great ball movement. Our playmakers did a great job of getting me open so the credit goes to them."

Butler (24-8) assisted on eight of its 10 first-half shots and 15 of 24 for the game while shooting 49 percent from the floor with eight 3-pointers on 19 attempts.

"We know whenever we move the ball from side to side, getting paint touches and things like that, that's when we're at our best," said Andrew Chrabascz, who hit 4 of 8 shots from the field and scored 12 points.

"I really liked their willingness and ability to share the ball for the most part in this game," Butler coach Chris Holtmann said. "We did some good things against a quality team."

Xavier Cooks paced Winthrop (26-7) with 23 points on 10-of-22 shooting from the field. Keon Johnson added 17 and Roderick Perkins contributed 13. Winthrop shot 40.3 percent for the game and went 9 of 24 from distance but made just 10 trips to the free throw line -- making five -- while the Bulldogs hit 20 of 30 foul shots.

"They were a big, physical team. (Chrabascz) is a great player, big guy," Johnson said. "They shot a lot of free throws. Most of the points came from the paint. So I think they got to the line like at least 30 times, somewhere around there."

Winthrop got off to a cold start, hitting 4 of 12 3-pointers and shooting 34.5 percent overall in the first half.

The long ball fell early for Butler, which hit 7 of 13 3-pointers in the first half. Woodson made five and had 15 points in the half as the Bulldogs shot off a 16-2 run and shot 52.2 percent from the floor to take a 41-27 lead into halftime.

"They jumped on us early and, you know, it's a hard team to come back on because of their style of play and things like that," Winthrop coach Pat Kelsey said. "So you credit them. Keon is the senior, and he's one of the best players in the history of this school, and I thought they did a very good job in their game plan in trying to contain him."

Winthrop's Johnson heated up early in the second half, scoring seven straight points to make it 48-41 with 13:19 to play, but Butler pushed the lead back to 17 with 7:17 remaining.

"We just stayed together as a team and talked defensively," Butler guard Kamar Baldwin said. "We were able to stop them from scoring and built the lead back up."

Butler advances to face Minnesota or Middle Tennessee on Saturday afternoon in Milwaukee.

NOTES: Butler came into the NCAA Tournament as a No. 4 seed, the highest in program history. ... The Bulldogs are 10-1 in their last 11 first-round games. They haven't lost in the first round since 2009. ... Winthrop is 1-10 all time in NCAA Tournament play. The Eagles' only victory came in 2007, when as an 11 seed they upset No. 6 seed Notre Dame 74-64 in the first round before falling to Oregon in the round of 32. ... Butler got a scare late in the game when Kelan Martin, the Bulldogs' leader in scoring and rebounding this season, went down with what appeared to be a knee injury. But he was able to return to the court and finished with 10 points and eight rebounds.