Ajla Tomljanovic explained she just had to block out the noise surrounding Serena Williams in order to progress at the US Open.

Williams' called time on her illustrious career following Friday's 7-5 6-7 (4-7) 6-1 loss to Tomljanovic, though did leave the door open to a possible return.

The 40-year-old had announced her impending retirement last month in Vogue, and before each of the three matches she played at Flushing Meadows, the tournament organisers paid tribute to the 23-time grand slam champion.

Williams had the backing of the crowd against Tomljanovic, who knew she had to cut through the background noise and focus on her game.

"I'd say the biggest thing was just to block out all the noise. At the end of the day I tried to keep it simple," she said.

"It's just another tennis match for me. I'm happy to be in the third round and have a great opportunity to play on Arthur Ashe. It's what I dreamed of when I was a kid. Just not make it bigger than it is because everyone else already made it huge.

"From the first moment I walked on court, I didn't really look around much. I was completely in my own little bubble."

Tomljanovic will face Ludmilla Samsonova in the next round and is already putting her win over Williams to one side.

"It's already kind of in the past. I mean, I'm happy I won, I actually think a little too quickly about the next one! I never feel like I have a problem with that. I have more of an issue chilling out and taking it easy the next day," she said.

Williams did not bow out without a fight, saving five match points in the deciding set before finally falling short.

"I stopped counting after the second [match point]," Tomljanovic said. "You know what, every match point she saved, it was all credit to her. I didn't feel like I did much wrong.

"I had this weird calmness because I felt like if I get broken, I mean, so what? Serena broke me. Wow, I'm just like the next person she broke when she's down 5-1.

"I know she comes up with her best tennis when she's in the most trouble. I didn't feel like I'm choking it away or something. I just kept calm and actually took a page of her book."