Serena Williams dropped out before the match against Maria Sharapova at Roland Garros. The tennis champion, who holds 23 Grand Slam titles, has recently returned to tennis after giving birth to her first child. On Monday, Serena gave a press conference and explained that she was unable to play because of a chest problem.

She had to face Maria for a place in the quarterfinals at Roland-Garros, the third match on center court Philippe Chatrier. Serena and her 37-year-old sister Venus Williams lost in doubles against María José Martínez Sánchez and Andreja Klepač on Sunday.

Right now I can't actually serve," Serena said, noting her injury has intensified since she first felt it during her singles match Saturday. "It's kind of hard to play when I can't physically serve."

Serena added that she would have an MRI on Tuesday and that she would see "as many specialists" as possible before deciding whether to attend Wimbledon in four weeks. "I'm beyond disappointed. I gave up so much from time with my daughter to time with my family. I put everything on the court, you know? All for this moment," she added. "So it's really difficult to be in this situation."

Serena was favorite against Maria, whom she has defeated 18 times in a row since 2005. Now that Serena has withdrawn, Maria will move directly to the quarter-finals, where she will be facing either Muguruza or Lesia Tsurenko. "It's difficult because I love playing against Maria," Serena said. "It's a match I always get up for. Her game matches so well against mine, and it is difficult, because like I keep saying, I've given up so much to be here." This is the second time she has forfeited a singles Grand Slam match. It would have been Serena's first match against Maria in over two years.

After the press conference, Serena posted a message on Instagram to speak directly to her fans. "We're still living to have the opportunity to have a second chance, I'm struggling, this is just the beginning," reassured the athlete emeritus to its 8.4 million subscribers. "Thank you for your support, I love you."