The Hawks completely erased a 19-point first-half deficit.

And an 11-point fourth-quarter deficit.

And won their most dramatic victory of the season.

Al Horford scored a basket with 33.4 seconds left and Jeff Teague hit a pair of free throws with 11.6 seconds left as the Hawks defeated the Rockets 121-115 Tuesday night at the Toyota Center. Horford’s game-winner came after a Rockets’ shot clock violation with the game tied at 115. He also hit a pair of free throws with 5.2 seconds left.

Horford, Teague, Paul Millsap and Kent Bazemore all scored more than 20 points for the Hawks.

The Hawks (21-13) have won seven of the past eight games and four straight over the Rockets. Coach Mike Budenholzer fouled Dwight Howard or Clint Capela on five of the Rockets’ final six possessions. The two went 6 of 10 from the line.

The Rockets (16-17) have lost two straight since defeating the Spurs on Christmas Day.

Here are the key players and five observations on the game:

Three key players

Al Horford: The Hawks center finished with a double-double of 30 points and 14 rebounds, including a career-high five 3-pointers.

Kent Bazemore: The Hawks guard had 26 points, including five 3-pointers.

James Harden: The Rockets guard nearly had a triple-double with 26 points, 10 rebounds and eight assists.

Five observations

1. Hawks back in it - twice

The Hawks trailed by as many as 19 points in the first half and by 15 at intermission. They came out with a big surge in the third quarter. They completely erased their deficit when Millsap hit a 3-pointer with 4:30 remaining in the period to tie the game at 82. The Hawks had 10 field goals in the run, five from 3-point range. However, the Rockets scored the next 10 points, nine from Harden, to regain a double-digit advantage. The Hawks had a shot blocked and three straight turnovers. Shelvin Mack converted a three-point play at the buzzer and the Rockets led 92-85 headed to the final period. The Hawks would trail by as many as 11 points in the fourth quarter before another run. They erased that deficit and took a three-point lead, 107-104 with 4:43 to play. It all set up the final-minutes drama.

2. Red-hot Rockets

The Rockets rarely missed in the first half. It was a back-and-forth game early. The Hawks trailed 26-25 with 3:34 left in the first quarter. The Rockets ended the period on a 15-0 run and scored the first basket of the second quarter. The Rockets outscored the Hawks 41-25 in the first quarter, the second-most points allowed by the Hawks in a quarter this season. The Rockets led by as many as 19 points in the first half and took a 71-56 lead at intermission. The Rockets’ point total was the most they have scored in any half and the second-most the Hawks have allowed in any half this season. The Rockets finished the half shooting 69.2 percent from the field (27 of 39) and 3-point range (9 of 13). At one point in the second quarter, the Rockets were shooting 73.5 percent from the field and 80 percent from 3-point range.

3. Korver shooting woes continue

Kyle Korver simply can’t find his shot in the past three games. He missed all 10 3-pointers on Tuesday. Combined with his 0 of 8 long-range game Monday, he missed 18 straight. Korver also went 1 of 5 from 3-point range against the Knicks Monday. In the past three games, Korver is 2 of 27 from the field and 1 of 23 from 3-point range.

4. Schroder on the bench

Dennis Schroder did not play in the game coming off a 2 of 8 shooting game in Monday’s loss to the Pacers. There did not appear to be an injury to the backup point guard. Coach Mike Budenholzer answered yes when asked before the game if everyone was available. Schroder sat near the end of the bench and never tied his shoes. Mack made an appearance, just his 12th of the season. Before the game assistant coach Darvin Ham asked Mack if he was ready to play, an indication the playing rotation was set without Schroder.

5. Tavares gets early playing time

With Tiago Splitter back in Atlanta nursing a calf strain, the Hawks went with little-used center Edy Tavares as part of the rotation. The rookie made just his fifth appearance of the season when he entered the game at the 6:11 mark of the first quarter. Tavares finished the first half and the game with six points and six rebounds.