LONDON - Roger Federer announced his retirement from tennis on Thursday after a career which brought 20 Grand Slam titles.

Here are five of his greatest matches.

1. 2003 Wimbledon final v Mark Philippoussis

Federer, who in 2001 knocked out his childhood hero and seven-time Wimbledon champion Pete Sampras in the fourth round on Centre Court, finally claimed his first Grand Slam with a masterclass victory over giant Australian Mark Philippoussis, 7-6 (7-5), 6-2, 7-6 (7-3).

"I proved it to everybody and it was a big relief because there was pressure from all sides, especially from myself, to do better in Slams," said 21-year-old Federer who despite his reputation had never previously got past the last-eight of a Slam.

2. 2008 Wimbledon final v Rafael Nadal

The 1980 final between Bjorn Borg and John McEnroe was widely regarded as the greatest championship match ever played at Wimbledon.

That was until 2008 when Rafael Nadal confounded critics who said his clay court supremacy would never translate to grass by beating Federer 6-4, 6-4, 6-7 (5-7), 6-7 (8-10), 9-7.

It was the Spaniard's fifth Major but first away from the French Open. He had two championship points in the fourth set and resisted an impressive Federer fightback to triumph in a rain-interrupted final which finished in near-darkness.

"I tried everything, got a little late, but look, Rafa is a deserving champion, he just played fantastic," admitted Federer.

3. 2009 French Open final vs Robin Soderling

Clay and Nadal had been Federer's nemesis for years. The French Open was the only Slam missing from Federer's resume - he had won his first seven Slam Finals to capture Wimbledon, the Australian and US Open - but repeatedly came up short in Paris.

Federer reached three straight finals from 2006 to 2008 and lost all to Nadal.

In 2009, Nadal was shocked by Soderling in the fourth round at Roland Garros, paving the way for Federer, who made no mistake, beating the Swede 6-1, 7-6, 6-4 for what remains his sole French Open crown.

"It might be the greatest victory of my career," said the 27-year-old, who equalled Pete Sampras's record of 14 Slams and became the sixth man to win all four Majors. "It takes away so much pressure. Now, I can play in peace for the rest of my career.

"Nobody will never tell me again that I have not won Roland Garros."

4. 2018 Australian Open final vs Marin Cilic

Federer's renaissance in 2017 - he won the Australian Open and Wimbledon - continued on his return to Melbourne as he swept into the final without dropping a set.

There he again faced Cilic, the Croat whom he had beaten six months earlier at the All England Club final.

The match went back and forth before Federer prevailed 6-2, 6-7 (7-5), 6-3, 3-6, 6-1 for his six Australian Open title. It was also his 20th Slam, making him the fourth player - after Margaret Court, Steffi Graf and Serena Williams - and first male to reach that landmark.

"I'm so happy, it's unbelievable," an emotional Federer said in his acceptance speech, before breaking down in tears. "Of course winning is just an absolute dream come true.

"The fairytale continues for us, for me. After the great year I had last year, it's incredible."

A month later in February, Federer became the oldest world No. 1 in the 45-year history of rankings at the age 36.

5. 2019 Wimbledon final v Novak Djokovic

Federer had two championship points but was unable to break the spirit of Novak Djokovic who triumphed 7-6 (7-5), 1-6, 7-6 (7-4), 4-6, 13-12 (7-3) as the longest ever final was settled by an historic tie-break.

The Serb claimed his fifth Wimbledon title, taking his Grand Slam tally to 16 after 4 hours and 57 minutes on a court where most spectators were firmly behind the 37-year-old Swiss.

"When the crowd is chanting 'Roger' I hear 'Novak'," said the Serb. "It sounds silly, but it is like that."

Federer said: "Similar to 2008 maybe, I will look back at it and think, 'well, it's not that bad after all'.

"For now it hurts, and it should, like every loss does here at Wimbledon."