Andre Agassi congratulated Roger Federer after the Swiss great replaced him as the oldest man to top the ATP world rankings.
Federer defeated Robin Haase in three sets to reach the semi-finals of the Rotterdam Open, meaning he will overtake old rival Rafael Nadal as the world number one when the rankings are updated on Monday.
At 36, Federer is the oldest player to top the ATP rankings and he will extend his record of 302 accumulated weeks at the summit.
Agassi previously held the landmark as the oldest player to be number one, with the American great 33 when he last held top spot in 2003.
But there are clearly no hard feelings about losing that distinction, with Agassi posting on Twitter: "36 years 195 days…
"@RogerFederer continues to raise the bar in our sport. Congratulations on yet another remarkable achievement!!"