ROME, Italy - Four-time Internazionali BNL d'Italia champion Serena Williams made a triumphant return to the Foro Italico, dismissing Sweden's Rebecca Peterson, 6-4, 6-2, to reach the second round where she may face sister Venus for the 31st time in their illustrious careers. 

GALLERY: Rulers of Rome - A decade dominated by Serena, Sharapova, and Svitolina

Forced out of the Miami Open due to a knee injury, the 23-time Grand Slam champion was playing her first match since March, but made up for lost time on Monday as she secured victory after one hour and 16 minutes on Court Centrale.

"It felt good to be back in the match," Serena said in her post-match press conference. "It's been a while. I haven't played a ton of matches this year. Not my choice, just by force. I really, really actually desperately wanted to be on the tour and to be playing, but it hasn't been able to work out.

"It felt good to finally be back out. Hopefully I'll be able to keep it up."

Williams played Peterson at the Hard Rock Stadium in what was her last completed match, surviving in three sets before pulling out of the event. 

"I actually haven't been able to train or practice a lot. I was out much longer than I expected.

"But I did everything I could to stay fit and to keep my cardio up. I knew that I love the clay season and I wanted to be a part of it. I literally did everything that I could, and I'm here."

Peterson, who made her Top 100 debut last year, appeared poised to push the former World No.1 towards another tough match as she saved break points in her opening two service games and established a 3-1 lead.

Seeded No.10 in Rome, Williams soon clicked into gear, winning five of the next six games to sweep theopening set, and broke twice more in the second to find herself serving for the match.

Peterson made one last stand in the final game - engineering two break points - but the American stood strong, saving both as she worked her way towards match point, converting her second to edge over the finish line.

Up next for Williams will be the winner of another blockbuster first round between Venus - who won the title in Rome back in 1999 - and Qatar Total Open champion Elise Mertens. The sisters last played at the 2018 US Open, where Serena won in straight sets en route to the final.

"We're just as fierce, Venus is just as fierce. We both really want to get some match play. We'll both do the best that we can."

They last played in Rome over 20 years ago, in what was their second career meeting back in 1998; Venus won that quarterfinal clash in straight sets.

"I vaguely remember that, so I don't really remember," Serena laughed. "But, yeah, it could happen. We play each other a lot. Seems like every tournament nowadays we meet early. Yeah, it is what it is.

"We'll see. She has a really tough first round. I'm really hoping she'll get through that, then we'll go from there."