It was Lopez's fifth straight double-digit scoring output and his third with 16 or more points in that span, during which he is averaging 15.6 points.
Bobby Portis scored 14 points, Justin Holiday added 13 and Zach LaVine totaled eight points and nine boards in his fourth game with the Bulls, as they won for the fourth time in five games.
Chicago hung around with defending champion Golden State before falling 119-112 on Wednesday, its only setback since a Jan. 8 loss to Houston that marked the Bulls' fifth loss over a six-game span.
Dennis Schroder paced the Hawks with 18 points and added five assists while Dewayne Dedmon registered a double-double with 11 points and 11 rebounds.
Kent Bazemore and Taurean Prince, the Hawks' second- and third-leading scorers, were held to nine and seven points, respectively.
Atlanta was limited to just 38 percent shooting (35-of-92) in the loss, which snapped a mini two-game winning streak. The Hawks had won three of four coming in.
Chicago was up 55-38 at halftime and led by as many as 25 in the second half.
A cutting dunk from John Collins with 2:04 to play in the third quarter brought the Hawks within 71-61, but the Bulls ended the period with a 77-63 advantage.
Atlanta never held a lead in the game.
Markkanen's key 3-pointer with 48.5 seconds left keyed the Bulls' 91-86 victory against the Hawks in Chicago in their first meeting on Oct. 26. The rookie had 14 points and 12 boards in that contest.
Chicago continues its three-game road trip Monday in New Orleans. Atlanta plays the fourth of six straight games at home Monday versus Utah.
--Field Level Media
Chicago | Atlanta | |
Robin Lopez 20 | Scoring | Dennis Schroder 18 |
Jerian Grant 6 | Assists | Dennis Schroder 5 |
Zach LaVine 9 | Rebounds | Dewayne Dedmon 11 |
Justin Holiday 4 | Free Throws Made | Kent Bazemore 4 |
Justin Holiday 2 | Steals | Dennis Schroder 2 |
Nikola Mirotic 1 | Blocks | Miles Plumlee 2 |
Team | Points | FG% | 3PM-3PA | FTM-FTA | Assists | Rebounds | Blocks | Steals | Turnovers |
Chicago | 113 | 50.0 | 14-32 | 19-21 | 31 | 48 | 1 | 8 | 16 |
Atlanta | 97 | 38.0 | 11-48 | 16-23 | 27 | 45 | 4 | 5 | 14 |