Djokovic tops teen "Ruuune!" at US Open in calendar Slam bid
Alexander Zverev, of Germany, returns a shot to Sam Querrey, of the United States, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/John Minchillo)

Alexander Zverev, of Germany, returns a shot to Sam Querrey, of the United States, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/John Minchillo)

Aug. 31, 2021 10:43 PM EDT
Holger Vitus Nodskov Rune of Denmark, reaches for a ball from Novak Djokovic, of Serbia, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Holger Vitus Nodskov Rune of Denmark, reaches for a ball from Novak Djokovic, of Serbia, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Aug. 31, 2021 07:50 PM EDT
Ashleigh Barty, of Australia, returns a shot to Vera Zvonareva, of Russia, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/John Minchillo)

Ashleigh Barty, of Australia, returns a shot to Vera Zvonareva, of Russia, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/John Minchillo)

Aug. 31, 2021 03:03 PM EDT
Alexander Zverev, of Germany, returns a shot to Sam Querrey, of the United States, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/John Minchillo)

Alexander Zverev, of Germany, returns a shot to Sam Querrey, of the United States, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/John Minchillo)

Aug. 31, 2021 01:32 PM EDT
Maxime Cressy, of the United States, returns a shot to Pablo Carreno Busta, of Spain, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Seth Wenig)

Maxime Cressy, of the United States, returns a shot to Pablo Carreno Busta, of Spain, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Seth Wenig)

Aug. 31, 2021 04:52 PM EDT
Bianca Andreescu, of Canada, reacts between points during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Bianca Andreescu, of Canada, reacts between points during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Aug. 31, 2021 11:45 PM EDT
Novak Djokovic, of Serbia, returns a shot during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Novak Djokovic, of Serbia, returns a shot during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Aug. 31, 2021 07:59 PM EDT
Ashleigh Barty, of Australia, waits during a break in play against Vera Zvonareva, of Russia, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/John Minchillo)

Ashleigh Barty, of Australia, waits during a break in play against Vera Zvonareva, of Russia, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/John Minchillo)

Aug. 31, 2021 03:17 PM EDT
Novak Djokovic, of Serbia, returns a shot during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Novak Djokovic, of Serbia, returns a shot during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Aug. 31, 2021 07:54 PM EDT
Novak Djokovic, of Serbia, returns a shot to during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Novak Djokovic, of Serbia, returns a shot to during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Aug. 31, 2021 10:44 PM EDT
Holger Vitus Nodskov Rune of Denmark, bottom, serves to Novak Djokovic, of Serbia, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Holger Vitus Nodskov Rune of Denmark, bottom, serves to Novak Djokovic, of Serbia, during the first round of the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Aug. 31, 2021 09:29 PM EDT
Holger Vitus Nodskov Rune of Denmark, left, and Novak Djokovic, of Serbia, meet at the net after Djokovic won their first-round match at the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Holger Vitus Nodskov Rune of Denmark, left, and Novak Djokovic, of Serbia, meet at the net after Djokovic won their first-round match at the US Open tennis championships, Tuesday, Aug. 31, 2021, in New York. (AP Photo/Frank Franklin II)

Aug. 31, 2021 09:40 PM EDT