Serena Williams has withdrawn from Roland Garros due to an achilles injury. The 23-time major champion announced her withdrawal ahead of her second-round match against Tsvetana Pironkova. The Bulgarian receives a walkover to the second round. 

"I really wanted to give an effort here. It's my achilles that didn't have enough to properly heal after the Open. I was able to get it somewhat better, but just looking long-term in this tournament, will I be able to get through enough matches? For me, I don't think I could.

"(I'm) struggling to walk so that's a tell-tale sign that I should try to recover"

"I warmed up and it was a very short warm-up. I talked to my coach and I was like, what do you think? What are your thoughts with this? We both thought about it and we really realized that more than likely it wasn't the best to try and play today."

Williams injured her Achilles tendon during her semifinal loss to Victoria Azarenka at the US Open two weeks ago. Prior to the tournament, Williams said she spent the time between the US Open and French Open rehabbing her injury at the Mouratoglou Academy, but acknowledged she was not 100% as the tournament started. 

"I feel like my body is willing," Williams said. "This is not a nagging injury, this is an acute injury. So if it was my knee that would be more really devastating for me. But this is something that just happened and it's super acute and that's totally different. I feel like my body is doing really really well and I just ran into, for lack of a better word, bad timing and bad luck, really, in New York. It happened, but my body is actually doing really, really well."

A three-time champion at Roland Garros, Williams kicked off her French Open campaign on Monday with a 7-6(2), 6-0 win over Kristie Ahn in the first round. This is the second time in the last three seasons that Williams has had to withdraw from Roland Garros due to injury, having to do so ahead of the Round of 16 in her comeback Slam in 2018.

"In my first-round match, in the second set I just felt like I needed to walk with a limp and that was no good. I had to focus on walking straight so I wasn't limping. I tried. I always give 100 percent, everyone knows that. Maybe even more than 100 if that's possible. I take solace in that. I think achilles is a real injury that you don't want to play with because that is not good if it gets worse."

The 39-year-old American said doctors have advised her she will need four to six weeks of rest before resuming full training. 

Pironkova will face either No.32 seed Barbora Strycova or Barbora Krejcikova in the third round. 

'I’m struggling to walk' - Serena Williams on her withdrawal from Roland Garros