The two freshmen combined for 17 of Kansas' last 19 points Monday night, helping the fifth-ranked Jayhawks hold off Missouri 80-77.
"I took it in my hands the last couple of minutes," said Collins, a backup guard who scored seven of his career-high 23 points in the final 2½ minutes.
Arthur, the Jayhawks' reserve center, had seven of his nine points after the midpoint of the second half to help Kansas (16-2, 3-0 Big 12) win its 10th straight and extend the Tigers' losing streak to four.
It was the second straight close finish for the Jayhawks, who needed overtime to beat Iowa State 68-64 on Saturday.
"I was a little surprised that we were both in there at the end," Arthur said. "Against Iowa State, we were both sitting down when it got close."
The Tigers (11-6, 0-4) have not won in Lawrence since a 73-61 victory on Jan. 24, 1999.
Missouri trailed by as many as eight points in the second half but led 72-71 when Marshall Brown hit two free throws with 2:57 left.
That's when Collins took over for the Jayhawks. His one-handed floater with 2:22 to go put Kansas up 73-72, and his fourth 3-pointer made it 76-72 with 1:42 to go.
"That's the Sherron that we recruited," coach Bill Self said. "It takes time for guys to get comfortable, and this was a big game for him. Sherron was the man tonight."
Missouri closed to 78-77 on Brown's two free throws with 44 seconds to go. Collins' basket 6 seconds later made it 80-77, and Missouri missed a chance to force overtime when Matt Lawrence airballed a 3-point attempt as time ran out.
"I'm kind of tired of this 'almost,'" said Lawrence, who hit four 3-pointers and led Missouri with 19 points. "We were almost there in a bunch of games this season. We need to start winning these when it comes down to the end."
Missouri's last possession came after a turnover by Kansas point guard Russell Robinson, whose ill-advised crosscourt pass drew an angry rebuke from coach Bill Self.
"God, he had a bad turnover late," Self said. "We had the game won and he threw the ball out of bounds."
Still, Self had few gripes about the close win.
"We were not our best tonight, but that was in large part due to Missouri playing great," he said. "We told our guys, 'They're 0-3, but they're better than that."
Kalen Grimes of the Tigers matched a season high with 12 rebounds, 11 on the defensive end.
Lawrence, who had three 3-pointers in the Tigers' first three Big 12 games, hit his third on Monday with just over 11½ minutes left in the first half. He didn't hit another until he connected with 9 minutes to go for a 65-60 lead.
His 19 points against the Jayhawks were 12 more than his season average of 7.1 -- so it was no surprise, Rush said, that the Tigers tried to go with their hot scoring hand in the closing seconds.
"He had lit me up all night," Rush said. "I guess they were trying to pick on me again with the last shot. They were setting a lot of screens for him, and it was hard for me to get around."
A 12-2 run, capped by Collins' three-point play, gave the Jayhawks a 58-50 lead with 13:43 to go.
Missouri responded with a 15-2 run, capped by Lawrence's last 3-pointer. But Arthur scored five straight points and put the Jayhawks up 69-68 on a basket from the lane with 3:43 to go.
"We had opportunities to take advantage of the game, but we came up with some empty possessions," first-year Missouri coach Mike Anderson said. "But you saw our guys. They fought, and I guess that's what the intensity of this great rivalry is all about. We left it all on the floor and just came up one possession short."
Kansas led by as many as nine points in the first half before leading 40-39 at the break.