• The 20-time Grand Slam winner admits he never foresaw regaining his status as world number one at 36.
  • Swiss says he believed he could win again after an injury-plagued 2016, though not at such a high level.
  • Federer: "I'm loving every moment that I can still stay on tour because you never know when it's going to end".

Roger Federer has reflected upon his "unbelievable journey" back to the men's tennis summit after making his first appearance since replacing Rafael Nadal at the top of the ATP rankings on Monday night [5 March].

The 36-year-old brushed aside second seed Grigor Dimitrov to win his third title at the Rotterdam Open last month, having already been confirmed as the oldest world number one in history as a result of reaching the quarter-finals in the Netherlands. It was the first time he has held top spot since October 2012.

That was the latest significant achievement in a remarkable resurgence from Federer, who has won nine singles titles since returning from a six-month knee injury layoff at the beginning of 2017. His three major triumphs in that time mean he is just the fourth player - and first male - ever to win 20 or more Grand Slams.

The increasingly selective Swiss may now fancy his chances of winning a second successive Sunshine Double amid an increasingly depleted field on the hard courts of Indian Wells and Miami over the coming weeks having rejected a wild card invitation from the Dubai Duty Free Tennis Championships. He is yet to announce his plans for the clay-court swing having completely avoided playing on the red dirt last year in a seemingly successful attempt to manage and preserve his fitness.

First on the agenda for Federer before the BNP Paribas Open - where he will have to reach the last four in order to retain his number one ranking - was his charitable foundation's fifth Match for Africa event in support of children's education in the region, which saw him preserve his unbeaten record over Jack Sock with a 7-6 (11-9), 6-4 exhibition win in front of a crowd of more than 15,000 at SAP Center in San Jose, California.

Before that singles contest, he teamed up with Microsoft co-founder and billionaire philanthropist Bill Gates for the second successive year to beat Sock and The Today Show co-anchor Savannah Guthrie 6-3 in a one-set doubles match.

During that event, Laureus Sportsman of the Year and Comeback of the Year award-winner Federer, who dropped to as low as 17th in the world before winning the Australian Open in 2017, admitted his surprise and elation at such an unexpected return to the pinnacle of his sport.

"Those are definitely special times in my life and my career," he said, per the Associated Press and The New York Times. "The dream as a little boy was to make it one day to world No. 1, but not at 36 years old I can tell you that. It was probably at some point at 25 maybe if things went really well.

"I had a tough year in 2016 with my knee and stayed positive, was resilient and fought to come back and really believed I could actually win again. I didn't think it was going to be at this level. It's been an unbelievable journey the last 14 months and my team has been incredible. I'm loving every moment that I can still stay on tour because you never know when it's going to end."

Per AP, the Roger Federer Foundation (RFF) had raised another $2.5m (£1.7m, €2m) by the end of Match for Africa 5 Silicon Valley.

Roger Federer
Roger Federer has enjoyed a remarkable 14 months since returning from knee surgery JOHN THYS/AFP/Getty Images