Two of the most recent American Grand Slam singles champions met for the first time on Monday at the National Bank Open presented by Rogers, where 2017 US Open champion Sloane Stephens defeated 2020 Australian Open champion Sofia Kenin in a dramatic Round 1 affair.

From 6-2, 5-1 up, Stephens needed six match points, separated by 90 minutes and two rain delays, to win 6-2, 6-7(5), 7-5 in an even 3 hours.

A former World No.4 and No.3, respectively, in the WTA rankings, Kenin and Stephens arrived in Toronto this week in much different places. Kenin, now ranked outside the Top 400, was competing at the WTA 1000 event on an injury-protected entry, having just returned to the Hologic WTA Tour last week in Washington, D.C. after more than four months off with an ankle injury. Stephens, down to No.59, was on a four-match losing streak dating back to her quarterfinal loss to Coco Gauff at Roland Garros in June. 

Will patience and persistence finally pay off for Sofia Kenin?

Straightforward 'til it wasn't: Stephens built a 6-2, 5-1 lead against Kenin in less than an hour. Then, it got complicated. Kenin saved two match points to hold serve in the seventh game, and turned away two more before breaking Stephens for the first time all match on her fourth chance in the next. A hold to 30 followed, and Kenin seared a forehand return winner to break again for 5-5. 

In all, Kenin's streak of games won hit five, and she was two points away from a sixth—and with it, the second set. Though Stephens held serve from 0-30 to force a tiebreak, the younger of the two Americans wouldn't be denied. She won four of the last five points of the tiebreak to take the match the distance. 

In photos: Slam champs Rybakina, Ostapenko advance in Toronto

The pair later navigated not one, but two, rain delays in the final set. The first came after the first game, where Stephens saved two break points to hold, and the second came with her leading 2-0, serving to lead 3-0.

Stephens again opened up a 5-2 lead, but nearly saw it slip for a second time. She lost the next three games, as Kenin saved a fifth match point en route to holding for 5-5, and stared at 15-30 on her serve at 5-5. From there, though, Stephens finally finished: She won seven of the last eight points.

"I don't think I've ever been in a match where I've had multiple match points over the course of the match and didn't lose my mind, so I'm just very proud."

- Sloane Stephens

An example of a stacked draw: Kenin and Stephens were two of seven Grand Slam champions scheduled in action at the WTA 1000 on its opening day of main-draw play. In the day session, there were wins for Wimbledon champion Elena Rybakina, two-time major-winning Simona Halep and 23-time Grand Slam champion Serena Williams.

Playing her first hard-court tournament in 18 months dating back to the 2021 Australian Open, Williams was a 6-4, 6-3 winner over lucky loser Nuria Parrizas Diaz of Spain.

Three takeaways: Serena wins first match in 430 days in Toronto opener

Sakkari for Sloane next: It won't get any easier for Stephens up next. No.3 seed Maria Sakkari of Greece awaits. They, too, have never played.