In his customary spotlight, Greg Monroe led the Hoyas with a season-high 19 points and 11 rebounds, but Vaughn added a career-high 14 points and matched his career best with eight rebounds and three blocks in Georgetown's 83-62 win over Mount St. Mary's on Monday night.
Clark, after setting career highs for points in his previous two games, added 12 points and four steals. He was a key defensive weapon for the Hoyas (5-0), who built a 20-point cushion by opening the second half with an 11-2 run.
"[Vaughn and Clark] are in their second year now," Georgetown coach John Thompson III said. "You see the growth, you see the development, you see their comfort level is higher. Their teammates' confidence in them and their confidence in themselves is better right now."
Chris Wright scored a season-high 18 points for the Hoyas, who improved to 21-5 against Mount St. Mary's.
After the Mountaineers cut it to 55-44 with 9:30 left, Monroe scored seven straight points during a 17-5 Georgetown run to put the game away. The spurt started with a basket by Vaughn.
Jean Cajou scored 16 points and Tayvon Jackson added 11 for the Mountaineers (3-3), who turned the ball over five times in the first four-plus minutes of the second half. They struggled against the Hoyas' size and tight perimeter defense.
"We played a very good team today," Mountaineers coach Milan Brown said. "Their size was able to bother us sometimes on the open looks that we had inside and they were still able to contest some of the shots that we had from the perimeter."
Vaughn, a junior who transferred from Florida State before the 2008-09 season, was the Hoyas' best big man for much of the night. Thompson called him a "presence," a phrase not often used during his first season with the team.
"[Last year] I put pressure on myself, but this year I definitely learned to relax," said Vaughn, who scored eight points in the second half. "I worked really hard this summer and I think I'm just trying to make sure it pays off by relaxing and playing hard."
In a quickly played first half -- only four combined fouls were called and one free throw was taken -- the Hoyas outscored the Mountaineers 16-8 over the final 9:08 to lead 40-29.
Wright hit three from beyond the arc and paced the Hoyas with 11 points while Monroe finished with nine points and seven rebounds. Cajou matched Wright's point total, hitting all three of his 3-point attempts in the half, but the Hoyas adjusted.
"For the second game in a row in the first half, we did not protect the 3-point line," Thompson said. "I think at the start of the second half our guys did a very good job of that, covering for each other, closing out and making sure they didn't get off shots."
Georgetown concludes its three-game homestand Saturday against American, while Mount St. Mary's continues a season-long seven-game road trip Thursday at Robert Morris.