Roger Federer has described his latest remarkable ascent to top of the ATP world rankings as the one that means the most to him.
The 36-year-old will become the oldest man to ever sit at the summit of the men's game on Monday after beating Robin Haase in three sets to reach the semi-finals of the Rotterdam Open, a run that will see him overtake old foe Rafael Nadal.
It is the crowning achievement of a stunning resurgence from the evergreen Federer, who was as low as 17th in the world in January 2017, having missed six months through injury in the previous year.
And Federer, now a four-time world number one, who holds the record for most weeks at the top with 302, believes this achievement outstrips the other times he held the title of best male player on the planet.
"I think reaching number one is one of the biggest, if not the ultimate, achievements in our sport," Federer, who was last number one in November 2012, said on court during a ceremony honouring his rise back to the top.
"Sometimes at the beginning you get there because you're playing so well, later you wrestle it back from someone else who deserves to be there, and when you're older you feel you maybe have to put sometimes double the work in.
"So, this one maybe means the most to me throughout my career, getting to number one and enjoying it at 36, almost 37, years old. It's a dream come true, I can't believe it."
Federer also, somewhat tongue-in-cheek, apologised to Haase, who had to sit through a farewell ceremony for the new number one's friend and retired compatriot Marco Chiudinelli in Basel last year.
"I'd also like to thank Robin for putting up a great fight, he's not been well all week," he added.
"Ironically, he has to go through another ceremony with another Swiss guy, six months ago in Basel he retired my good friend Marco and now he has to watch this, I'm sorry you have to watch these things!"
|Kovac: Madrid strong without Ronaldo, Messi is the best|
|ATP suspends umpire Lahyani over Kyrgios ´pep talk´ at US Open|
|North and South Korea seek to co-host 2032 Olympics|
|Ampadu signs long-term Chelsea contract|
|Don´t blame Neymar, PSG players all guilty - Thiago Silva|
|Real Madrid seek to plug Ronaldo scoring gap – Champions League in Opta numbers|
|Brewers allow Cardinals to inch closer with loss to Reds|
|Manchester is still red – Depay ahead of Lyon´s clash with City|
|Orioles become first pro team to wear braille jerseys|
|Klopp hails ´brilliant´ Henderson|
|PSG attack lacked aggression, says Tuchel|
|Atletico Tucuman 0 Gremio 2: Libertadores holders draw first blood in QFs|
|Thomas plays down wrist worry|
|Rakitic wants more from Barcelona hat-trick hero Messi|
|My players aren´t s*** – Pochettino defends Spurs squad|
|Cubs reliever Morrow won´t return this season|
|Tebow expected to be back in Mets organisation next season|
|Inter can compete against anyone – Icardi revels in Champions League victory|
|Tuchel: PSG loss to Liverpool not logical or correct|
|Sturridge in best shape I´ve seen – Klopp|
|Milojevic celebrates ´fantastic´ occasion after Red Star´s 26-year wait|
|Rodrigo and Simeone salute Griezmann display|
|Seahawks DE Clark on Bears QB Trubisky: He´s nothing special|
|Carroll says Wilson has been ´over-trying a little bit´|
|Judge returns to Yankees´ starting lineup|
|Napoli boss Ancelotti takes aim at Red Star time wasting|
|Favre admits young Dortmund stars struggled in Bruges|
|Otavio would trade goal for Porto victory as he bemoans Schalke draw|
|Championship Review: Pacesetters Leeds crush Preston, Villa end five-game winless run|
|Neymar world-class but not a defender - Klopp says Liverpool targeted PSG star|
|Waiters injury update: Heat guard unlikely to be ready for start of season|
|Gojowczyk eliminates returning Tsonga in Metz|
|Liverpool enjoying best start in 57 years after PSG win|
|Galatasaray 3 Lokomotiv Moscow 0: Terim´s side make light work of Russians|
|Club Brugge 0 Borussia Dortmund 1: Super sub Pulisic scores late winner|
|Schalke 1 Porto 1: Fahrmann saves one penalty, but Otavio scores another|
|Red Star Belgrade 0 Napoli 0: Points shared as Italians fail to make possession pay|
|Liverpool 3 Paris Saint-Germain 2: Firmino strikes late as Reds edge five-goal thriller|
|Monaco 1 Atletico Madrid 2: Costa and Gimenez seal comfortable win|
|Chaos reigns in Serie B as league denies suspension claim|
|India secure Asia Cup victory despite valiant Hong Kong effort|
|Messi makes "extraordinary routine", says Valverde after Barca star surpasses Ronaldo|
|Spalletti´s Inter to take heart from Tottenham turnaround|
|Casillas features in landmark 20th Champions League campaign|
|Spurs deserved more from best performance of the season - Pochettino|
|Brown absent from Steelers facility on Monday due to ´personal matter´|
|Toronto´s Bussey given eight-match biting ban|
|Barcelona 4 PSV 0: Marvellous Messi lights up Camp Nou|
|Inter 2 Tottenham 1: Icardi, Vecino complete dramatic late turnaround|
|Allegri, Chiellini defend Costa over spitting ban|
|Firmino only fit enough for bench duty|
|Kovac applauds Sanches ahead of Benfica homecoming|
|Tomlin confirms Steelers WR Brown was absent from facility on Monday|
|Mourinho tells United to follow Federer´s lead amid Young Boys pitch concerns|
|Costa banned for four Serie A matches for spitting|
|PGA Tour announces changes to FedEx Cup Playoffs format|
|Rashford to start against Young Boys, Mourinho confirms|
|Ryder Cup heading to Congressional in 2036|
|I never listen to stupid things - De Gea unconcerned by criticism|
|Aguero trains as Mendy sits out Man City session|
|Lampard fined after accepting improper conduct charge|
|Serie B suspended after Pro Vercelli win appeal|
|Mitchell returns to England as defence coach|
|Brady completes Cornet upset in Guangzhou|
|Lopetegui giving no guarantees to ´fighter´ Navas|
|Di Francesco denies racially abusing Costa|
|Saunders apologises for ´sickening´ online video|
|Tianjin Quanjian 0 Kashima Antlers 3 (0-5 agg): Semi-final spot booked in resounding fashion|
|Madrid cannot live on Ronaldo´s glories, warns Ramos|
|Real Madrid are Champions League favourites, insists Man City coach Arteta|