The Hawks, who began the night percentage points behind the New York Knicks in the race for the eighth playoff spot in the Eastern Conference, set a season high with 39 first-quarter points and never trailed.
Atlanta had lost seven of eight but recovered with strong games by Scott and Jeff Teague, who had 20 points and 12 assists.
The Cavaliers, who had won five of six to move within two games of the Hawks and Knicks, lost an opportunity to possibly move within a game of eighth place.
Scott made 12 of 13 shots from the field. Scott, a backup forward, had a combined 16 points in his past four games. He topped that with 18 in the first half.
The Hawks had six 3-pointers while setting a season high for first-quarter points in taking a 39-23 lead. Atlanta committed nine turnovers in the second quarter, but Cleveland still outscored the Hawks only 26-22 in the period and trailed 61-49 at halftime.
As Cleveland opened the second half with almost 5 minutes without a field goal, Teague took over for Atlanta. Teague had nine points in the third period, including three straight baskets and a driving layup to beat the buzzer at the end of the period.
Teague added two 3-pointers in the last 3 minutes as the Cavaliers never mounted a serious challenge.
NOTES: The Hawks completed a sweep of the three-game series. ... The Hawks shot 58.5 percent from the field. ... After missing one game with a sore right shoulder, Cavs' C Anderson Varejao had nine points and five rebounds in 27 minutes. ... Irving played his second game after missing eight games with a torn bicep muscle. ... Hawes had 13 points in the third period.