Washington's Caron Butler hit a three-pointer with 1:10 to play to tie it at 98 after Atlanta had a 17-point lead early in the third quarter.
Darius Songaila's turnover with 31.8 seconds left gave the ball to Atlanta. Mike Bibby, who led the Hawks with 21 points, fed Horford for a layup, and Butler fouled him. Horford, who had 19 points, 13 rebounds and six assists, hit the free throw for a 101-98 lead.
Antawn Jamison led Washington with 26 points and 13 rebounds. Butler had 21 points and 10 rebounds. Songaila scored 16 points.
Washington played its third game under interim coach Ed Tapscott. After winning their first game against the Golden State Warriors, the Wizards have dropped their past two and are just 2-12 this season.
It was a case of the Wizards falling far behind and not being able to take a fourth-quarter lead.
"So much energy trying to get back from [17 points down] that you're fatigued at the end," Tapscott said.
Knicks 138, Warriors 125:: Chris Duhon had a franchise-record 22 assists, David Lee had career highs of 37 points and 21 rebounds, and host New York rang up a record-setting 82 points in the first half. The Knicks raced to an 82-64 halftime lead to shatter the record for most first-half points at the present Madison Square Garden, set when Kansas City scored 81 on Dec. 8, 1979. Al Harrington, acquired from Golden State last week, added 36 points and 12 rebounds for the Knicks. Corey Maggette led the Warriors with 32 points and 12 rebounds.
Thunder 111, Grizzlies 103:: Kevin Durant scored 30 points to help Oklahoma City end a 14-game skid. The win was the Thunder's first on the road and second of the season. Memphis has lost 10 of its past 11. O.J. Mayo led the Grizzlies with 30 points.
Cavaliers 97, Bucks 85:: LeBron James scored 11 straight points for visiting Cleveland late in the fourth quarter and finished with 32 points. Michael Redd returned after missing 14 games with a right ankle sprain and led the Bucks with 20 points.
Rockets 103, Spurs 84:: Luther Head scored 21 points in place of Tracy McGrady (knee), and host Houston used balanced scoring to beat San Antonio. The Rockets will be without McGrady again today. Tim Duncan had 17 points for the Spurs.
Nuggets 106, Timberwolves 97:: Chauncey Billups scored a season-high 27 points in three quarters, Carmelo Anthony (Towson Catholic) added 25 points and 10 rebounds, and visiting Denver beat Minnesota for the seventh straight time. Randy Foye scored a season-high 25 points for the Timberwolves.
Off the court
Magic: : Mickael Pietrus will be out three to five weeks because of a torn ligament in his right thumb. Pietrus averages nearly 13 points and is one of the Magic's main three-point shooters. The injury leaves an already thin Orlando backcourt even thinner.
Knicks: : President Donnie Walsh said he would probably talk to guard Stephon Marbury and his representation from the players association tomorrow. Marbury, who has been on the inactive list most of the season, was suspended and fined after the Knicks said he refused to play Wednesday.