Justine Henin-Hardenne put her victory over Svetlana Kuznetsova in Saturday's French Open final down to nerve.
Henin-Hardenne did not drop a set on her way to winning the title
The Belgian retained her title and claimed a fifth Grand Slam crown with a 6-4 6-4 win.
"The difference is how you manage your nerve," she said. "No one sleeps well the day before a Grand Slam final.
"During these two weeks I have been able to accept that some things were not going my way. I have been able to turn situations by keeping calm."
It was not Henin-Hardenne's best display by any means and she admitted: "I have not played my best tennis, neither today nor during the tournament."
The Belgian, who was sidelined for months during 2004 with an energy-sapping illness, also said was she exhausted after her run to a third Roland Garros title in four years.
It was the same picture as usual when I play against Justine
"I lose a lot of energy during a Grand Slam because I cannot sleep well," she said. "Physically I did suffer a lot. I was feeling very tired.
"When she came back into the match I tried to play point after point, but I played my best in the crucial games."
Kuznetsova said that a string of errors in the opening stages, particularly on her more potent forehand, were key to her defeat.
"I was just overdoing it," she said. "I just missed my chances. I had so many of them. If you don't use your chances, you don't win matches."
The Russian has now lost 11 of her 12 matches against Henin-Hardenne.
"It was the same picture as usual when I play against Justine, it seemed so similar to other matches.
"I didn't use the chances I had and she hit the lines with her serve at some important moments.
"If you keep losing, keep missing, you keep letting her back, then it's not possible to win. That was the key."