Only three weeks ago in Monte Carlo, the clever Frenchman humiliated Pete Sampras, 6-1, 6-1, inflicting on the Wimbledon champion his worst defeat for eight years. "I dug a big hole for myself," Sampras said.
Santoro's performance yesterday suggested that he was longing for a hole to save him from further embarrassment. He arrived for the Italian Open saying he was tired after competing in Hamburg last week, and was simply no match for Henman, who appears to have gained from the adversity of struggling to master the sport's slowest surface.
It will be interesting to see if Henman's improvement continues in his second round match, in which he will play either Marcelo Rios, the brilliant young Chilean groundstroker who was briefly No 1 in the world until sidelined by an elbow injury, or Marzio Martelli, an Italian wild card, ranked No 140.
Unfortunately, Greg Rusedski was unable to contribute to Britain's success yesterday, having played and lost in the first round to the Czech Bohdan Ulihrach, 7-5, 7-6, in the opening match on Court No 5. Rusedski, the world No 5, although frequently out-smarted by an opponent more comfortable on the surface, served for the opening set at 5-3 and was unable to convert any of three set points in the second set.
Henman's only previous clay court victories on the mainstream ATP Tour were achieved against Sweden's Jan Apell in Hamburg last week, against Germany's Jens Knippschild in Munich the week before, and against Spain's Roberto Carretero, who was ranked No 334 in the world when he retired hurt in the first round here last year with Henman leading, 4-6, 7-5, 2-0.
Even allowing for Santoro's shortcomings, Henman gained a good deal of confidence from being able to impose his game on the Frenchman for all but a couple of the 61 minutes they were on court. Santoro did not win a game until he was 0-5 down, and much of his play was woeful.
One of his most animated responses came after Henman struck a backhand volley directly at his body in the third game of the second set. Santoro managed to deflect the ball with his racket, and then appeared to spit towards the net. The umpire, Romano Grillotti, had a word with the Frenchman during the changeover.
Henman described the win as a "big boost", a performance he placed alongside those against Petr Korda and Carlos Moya on the concrete courts at the Lipton Championships in Key Biscayne.
He emphasised that, "to beat someone like Santoro is a pretty good win for most people, but for me it's a very good win. I went into the match as an underdog, probably by a long way. A lot of people would have bet on Santoro. But I've improved a lot since Monte Carlo. I can stay in rallies much longer."
The British No 2 acknowledged that the court was faster than he expected and said his game was also helped by the balls, which were lighter than the ones in Germany. Rusedski was unable to capitalise as much as he ought to have done, admitting that, "I had opportunities and didn't take them."
Rusedski was unable to take any of four break points in the fourth game, but recovered immediately after losing his serve for 3-2 and double-faulted on the concluding point when serving for the set at 5-3.
He was then trapped in midcourt when Ulihrach lobbed to win the set, one of several occasions that the Czech's cunning paid off.
After saving break points at 4-4 and 5-5 in the second set, Rusedski screamed in anguish as he missed a low backhand volley on his first set point at 6-5. He led 3-0 in the tie-break, but was overhauled and had to save a match point at 5-6 before creating two more set points, at 7- 6 and 8-7.
Rusedski then double-faulted to offer Ulihrach a second match point at 8-9, hitting a service return high and wide and then hurling his racket towards his chair, knocking over a waste bucket.
Rusedski was not the only frustrated player. Petr Korda, the second seed, was eliminated, 6-2, 6-4, by Hicham Arazi, of Morocco.