MONTRÉAL, Canada - As she crosses the border to go to the Rogers Cup in Montréal, Serena Williams crosses yet another milestone in her illustrious career - on Monday she reaches 200 career weeks as World No.1, just the fifth player since the inception of the WTA Rankings in 1975 to do so.
The record-holder for most career weeks as World No.1 - Stefanie Graf, who got all the way to 377, which is in fact the most ever, male or female - talked to wtatennis.com about what makes it so hard to rack up these kinds of tallies at No.1, and what an achievement it is for the current World No.1.
"I think this is an incredible achievement, one that's not easy to reach but certainly well-earned," Graf said of Williams' newest milestone. "I'm sure she has more milestones to look forward to.
"Being at your best all the time in a year-round sport is all-consuming. Add to it being the best as you set the bar makes it more exhausting - physically, mentally and emotionally.
"Keeping that up for almost four years is remarkable."
Graf knew early on that Williams would become one of the all-time greats. Their paths crossed just twice, and both times in 1999 - Graf's last season and Williams' breakthrough season. They played at Sydney (with Graf winning, 6-2, 3-6, 7-5) and Indian Wells (Williams winning that one, 6-3, 3-6, 7-5).
"Athletes have their own perspectives as to why a match would be great or not, but what was very clear to me when playing her was that she had a bright future ahead," Graf commented.
"She seemed to have all that any player could hope for."
While Williams has been piling on the weeks at No.1 this year, she has been stuck at 17 Grand Slams all year with earlier-than-expected exits at the Australian Open, French Open and Wimbledon. But for that to even be a talking point speaks volumes about the player in question - and the US Open has been a stronghold for Williams since coming back from her year-long injury and illness lay-off, the only Grand Slam she has won twice since then. In a few weeks she will try to three-peat in New York.
Williams has been down this road before.
"I got stuck at 13 for a while and I was really depressed about it," Williams said last week from Stanford, where she won her WTA-leading fourth title of the year. "I was thinking, 'I'm never going to get to 14.' I was there for a while. I keep saying I don't think about the numbers, but everyone was talking about it, and maybe subconsciously it was getting in my brain, just twirling in my mind.
"But then I just thought, 'Serena, don't put pressure on yourself. Just relax.'
"And I just need to relax now and remember that time. I've been there before. If it doesn't happen this year, there's always next year, and I have no points to defend next year, so it looks good!"
Graf, who holds the Open Era record with 22, was asked if Williams will win more Grand Slams.
"While I don't have a crystal ball, living in Las Vegas I've come to appreciate odds," she said.
"My answer would be yes."