Tennis world reacts to Federer's historic return to No.1 spot

After Swiss tennis star Roger Federer became the oldest world number one when he reached the semi-finals of the Rotterdam Open, tributes started pouring in for the 20-time Grand Slam winner from current and former players.

The 36-year-old made a historic return to numero uno spot by overcoming an early scare from Netherlands' Robin Haase to clinch a 4-6, 6-1, 6-1 triumph and book his place in the semi-finals of the Rotterdam Open.

Federer would now replace old rival Rafael Nadal at the top of the rankings

From German tennis great Boris Becker to Arsenal footballer Mesut Ozil all took to their Twitter account to wish Federer for achieving the historic feat.

Here are some tweets:

Former Grand Slam champion Andre Agassi: 36 years 195 days...@RogerFederer continues to raise the bar in our sport. Congratulations on yet another remarkable achievement!!

From German tennis great Boris Becker:@rogerfederer continues writing history!!! #goat @ATPWorldTour

Former German tennis player Nicolas Kiefer: Congratulations @rogerfederer on another amazing achievement! The oldest player to become World No. 1 on the @ATPWorldTour at age 36. #Federer #GOAT

American tennis coach Brad Gilbert: congrats to RF2.0 @rogerfederer amazing accomplishment back at #1 at 36 years young.

Former Swiss player Jonas Bjorkman: WORLD NR 1 again! @rogerfederer is like a good bottle of wine who just gets better with age;). Amazing accomplishment!

Arsenal footballer Mesut Ozil: Back to where he belongs at world number #1. Congratulations @RogerFederer

Former South Africa golfer Gary Player: Congratulations @rogerfederer back at World #1. Respect. Age is just a number. GOAT

By becoming the oldest number one male player, Federer surpassed eight-time Grand Slam winner Andre Agassi, who previously held the record at 33 years since September 2003.