The American lost just the one set in Rome and her 6-3, 6-0 demolition of former French Open finalist Sara Errani in the final served notice that she is back to her steamroller best. (Agencies)
Williams enjoyed an outstanding 2013 when she posted career highs in match wins (78) and titles (11), including her 16th and 17th major championships at Roland Garros and US Open.
But this year has been much more of a struggle with a fourth-round exit to Ana Ivanovic in the Australian Open followed by a stunning opening-round defeat to 78th-ranked Jana Cepelova in Charleston.
That upset left Williams saying she felt "really dead" and in need of a long layoff, which she duly took up until her return at the Madrid Masters two weeks ago.
She was forced to retire from that tournament at the quarter-final stage with an injured left leg, casting renewed doubts on her hopes of winning a third French Open title.
But her romp in Rome just a week later restored her as an overwhelming favourite to win in Paris at the annual consecration of the claycourt season.
"I am like fine wine. I am getting better with age," Williams said then although she still had doubts about her fitness going into the year's second Grand Slam event.
"I feel better but I am not 100 percent. I am going on adrenaline at the moment, so I'll take a couple of days off. I hope to win one more Grand Slam before I retire, but I don't want to look too far ahead. There are hundreds of players who want to do the same,” Williams said.
One more Grand Slam win would have great significance for Williams as it would put her level with legends Chris Evert and Martina Navratilova on the all-time winners list with 18 singles titles, and leave her just four shy of the Open-era record held by Steffi Graf.
Evert for one believes she can add to her Grand Slam haul if she puts her mind to it.
"For her high standards, it's been an erratic season," she said. "But she can turn it around on a dime. One day she looks slow and mopey. The next day she returns with fire in her eyes."
A fully-fired up Williams should be too tough a prospect for the rest of the French Open field, especially in the prolonged absence through injury of Victoria Azarenka, the former world number one from Belarus who has given the American plenty of trouble in the past.
On the face of it fellow 32-year-old Li Na, the second seed, is best placed to take advantage of any waverings from the American.
The Chinese icon, won the second Grand Slam title of her career at the Australian Open four months ago, her first being her historic triumph in the French Open in 2011.
But Li lost 7-5, 6-1 to Williams the last time the two played each other in the final at Miami in March and her claycourt form of late has been patchy.
She is a proven winner at Roland Garros though and can count on the Paris crowd being firmly on her side should the seedings hold up and the pair meet again in the final on June 7.
Four other former winners will be in the field, with both Maria Sharapova (2012 winner) and Ana Ivanovic (2008) capable of going all the way once again.
A late covert to claycourt tennis, Sharapova won back-to-back titles in Stuttgart and Madrid in the buildup to Paris before losing to Ivanovic in the second round in Rome.
Ivanovic was the only player to take a set off Williams in Rome and has been showing signs lately that she is beginning to rediscover the kind of form that made her world No.1 in 2008, the year of her French Open triumph, her only Grand Slam title to date.
Elsewhere there will be interest in whether rising stars Simona Halep of Romania and Eugenie Bouchard of Canada can underpin their pedigree by going deep into the tournament for the first time.
The American lost just the one set in Rome and her 6-3, 6-0 demolition of former French Open finalist Sara Errani in the final served notice that she is back to her steamroller best.