McGuire, a forward making a start in the backcourt, had 15 rebounds and led Golden State's defensive efforts against Joe Johnson as the Warriors answered a late comeback by Atlanta to beat the Hawks 85-82 on Wednesday night.
"Just incredible," Warriors coach Mark Jackson said of McGuire. "He embodies everything we've preached about since Day 1, and I thought the important thing is to make a statement and to start the guy that has done everything we've asked him to do."
David Lee scored 22 points, including the go-ahead basket with 30 seconds remaining.
The Warriors took the lead early in the second period and protected the lead until Zaza Pachulia scored on a follow-up shot after a miss by Teague with 52 seconds remaining for a 78-78 tie.
Lee drove past Pachulia to score with 30 seconds remaining to give the lead back to Golden State.
Monta Ellis had 24 points and eight assists, while Lee had 12 rebounds for a double-double. McGuire, a fifth-year player from Fresno State, held Johnson to 18 points on 6-of-17 shooting.
Curry missed all but the final 3 seconds of the game due to a strained tendon in his right foot.
Jackson said he knew after Wednesday night's loss at Indiana he was going to move Ellis from shooting guard to point guard against Atlanta. He said he was "tossing and turning" as he tried to pick a new starter at shooting guard. The surprise choice was the 6-foot-9 McGuire.
"I knew exactly what I was going to get from him: Great defense, goes after every rebound, even down the stretch," Jackson said.
McGuire called his assignment on Johnson "nothing special."
"The same thing I do every game: I just get down and play defense," McGuire said. "If I'm out there long enough, I'm going to get rebounds, that's guaranteed."
The Hawks were held to a season-low 33.7 percent shooting as they missed 61 of their 92 shots from the field -- many from long range.
Hawks coach Larry Drew issued a familiar criticism of his players' shot selection.
"We settled tonight, particularly the first half," Drew said. "I thought we settled for way too many jump shots. We've got to be smarter and understand the flow of the game. It's one thing if you're making shots, but if you're not making shots from the perimeter you can't just settle for jump shots."
The Hawks also were hurt by poor shooting on free throws, making only 16 of 26 attempts. The Warriors made 16 of 17 free throws.
Josh Smith, who had 14 points and 10 rebounds, made only five of 20 shots from the field and four of eight free throws. He made only two of 11 shots in the final period.
"I thought we missed a lot of point-black shots with nobody around," Johnson said. "I'm sure we'll bounce back and have to get the next one, but it was definitely a tough loss for us."
Johnson returned after missing two games and the All-Star game with tendinitis in his left knee. He wore wraps on each knee and said his left knee was "a little stiff" at times. Johnson appeared to lack explosion when he missed a layup in the first half after managing only a tentative jump toward the rim.
"I wouldn't say I was 100 percent, but I was decent," Johnson said.
Johnson sank a jumper on the first possession, but it was his only basket of the half. He missed his last seven shots of the half but regained his form as he delivered Atlanta's first three baskets, including a 3-pointer, in the second half.
The Hawks set a season low by making only 32.6 percent of their shots from the field in the first half. The Warriors led 48-38 at halftime and 64-61 after three periods.
Hawks C Al Horford said he has been cleared to begin rehabbing from his surgery for a torn left pectoral muscle. ... McGuire's 11 rebounds in the first half were a high for any Golden State player this season. The Warriors had a 33-18 advantage in rebounds in the half and set a season high with 53 rebounds for the game. The Hawks had 50. ... Hawks F Vladimir Radmanovic reported to Philips Arena, but was sent home with an upset stomach.