Two players - Pete Sampras and Andre Agassi - travel to Paris needing the French title to complete the set. Sampras has been in that position for the past four years, and having won 10 Grand Slams, leaving him two short of Roy Emerson's record of 12, the focus will again fall on him.
But an equally plausible outcome is that his old rival, Agassi, will beat him to the full house. Agassi has been in two French Open finals (1990 and 1991), and his game lends itself more to the clay than Sampras's. Agassi's fortunes are in the ascendant as he showed by reaching the final of the clay-court BMW Open in Munich; Sampras's form this year has been decidedly patchy.
Yet who would have believed six months ago that Agassi would be tipped to win at Roland Garros? At the end of a year in which he won just 12 matches out of a meagre 24 played on the tour, his ranking had sunk to 141 and he was left playing the second-level Challenger tournament in his home city of Las Vegas. He couldn't even win that, losing in the final to the little-known Christian Vinck.
However, Agassi has always said his form fluctuates, and refuses to see this year as a comeback - as he was never away. "My results have always gone up and down, and of course last year was a bad one, but I kept working at it.
"I've been practising well now for a few months, but until recently I haven't brought that into matches. Now it's starting to come, I'm actually playing matches like I've been practising, and that's good for your confidence. Even if you lose a match, if you can go out next day and play real well in practice you know it's coming around."
Looking back over Agassi's career, four bursts of achievement are discernible: his rush to prominence in denim shorts and long bleached hair in 1988, which saw him reach the Roland Garros semi-finals as an 18-year-old; his three abortive Grand Slam finals (two French, one US Open) in 1990-91, culminating in his dramatic surge to the 1992 Wimbledon title; his run to the US Open title in 1994, which he won unseeded (ranked 20) and then cruised to the 1995 Australian Open and the No 1 ranking; and this year's resurgence, which has so far brought him two titles and could bring a third today. Between these surges he has often looked totally out of it.
Agassi was always destined to play tennis. His father Mike, who represented Iran in boxing at the 1952 Olympics, hung a tennis ball over the crib of baby Andre, and before he was two he was hitting balls. Such early hand-eye coordination made him a local celebrity, and there is family footage of a four-year-old Agassi hitting with Bjorn Borg, Jimmy Connors and other greats.
Such expectation brings pressure, but Agassi found an outlet for both his rebellious tendencies and his immense tennis ability at the Nick Bollettieri tennis academy in Florida. The man who took him to No 1 and his two other Grand Slam titles is Brad Gilbert, another tennis rebel but the kind of anti- establishment figure that Agassi for so long admired.
In the 30 years of open tennis, eight men have finished their careers with three of the four major titles (Rosewall, Newcombe, Nastase, Connors, Lendl, Wilander, Edberg and Becker). It would be an irony for Sampras if only Agassi's fourth Grand Slam title were to give him the full set, but it has to be a possibility on Agassi's current form.
Agassi himself says of the French: "I feel good about it, the best time I'm having in my career is now. You can't say I can win the tournament until the last weekend, but it's nice to have a look at the basket."