Serena's lovely message for comeback star Kvitova

Serena Williams has shared a message of support for Petra Kvitova, who won on her competitive return just six months after being stabbed in her home.

The Czech left-hander breezed into the second round of the French Open on Sunday night with a 6-3 6-2 win over American Julia Boserup.

The victory was an emotional one for the 27-year-old, who dropped her racquet and hid some tears behind her hands after match point.

A two-time Wimbledon champion, Kvitova spent five months out of the game after undergoing emergency surgery in December when she was stabbed during a home invasion.

Kvitova was overcome after her win. Pic: Getty

Kvitova captioned a picture of herself celebrating the win over Boserup with the words 'Thank you' and a loveheart.

World No.2 Williams, who announced her pregnancy in April and is sitting out the rest of the year, replied with a heartwarming note for her rival.

"So amazing to see. So proud and happy for you. This is truly an amazing comeback," Williams wrote on Twitter.

The two stars have met six times on tour, with Kvitova defeating Williams in their last clash - a straight-sets win in a 2015 Madrid Open semi-final.

Fellow tour professional Victoria Azarenka had described Kvitova as a 'warrior' for being so positive so soon after the attack.

"I thought it was so amazing after a few months to not be traumatised (by) being in public and stuff," Azarenka said yesterday.

"She is such a warrior. Just seeing her here being in a good mood, healthy and playing is a win overall."

Kvitova had reveled in the Roland Garros victory on the first day of the tournament, saying she just feels lucky to be playing tennis.

This match is special to me. I won for the second time, if I can say," she told reporters after the match.

"It wasn't really about the game today. Yesterday I was thinking how everything would be, and I couldn't really imagine how it would be.

"I thought maybe I'd cry when I'd step on the court, but I didn't today.

"Normally I can control my emotions on the court and I'm so I'm happy that I kind of did it, as well, this time."

Kvitova will face another Amerian, Bethanie Mattek-Sands, in the second round tomorrow night.

with AAP