Naomi Osaka is back into the quarterfinals of the Miami Open for the second year running after a 6-3, 6-4 win over American Alison Riske in Monday's Round of 16. 

Osaka is in a vastly different place than she was at this time last year. She was ranked World No.2 when she arrived in Miami last year as the reigning Australian Open champion and a quarterfinal loss to Maria Sakkari snapped her 23-match winning streak. Now ranked No.77, Osaka has now won three consecutive matches (plus one walkover) for just the second time since she reached the last eight a year ago. She won three matches at the Melbourne Summer Set 1 in January before withdrawing due to injury. 

Playing Riske for the first time since 2019, Osaka snapped a 1-1 head-to-head tie between the two with a 92-minute victory. 

"I felt a bit rusty because I haven't played in three days, so [I was] just kind of trying to get back confident and into the groove of things," Osaka said. "The last time I played her, it's been a couple of years, and knowing that she's a really tough opponent and knowing she's a bit unorthodox, I would say, the trajectory of her balls were quite difficult for me."

Match management: Three games were crucial to Osaka's effort in victory. She started the match with a nearly 10-minute service hold that extended to six deuces, saving four break points along the way. She broke Riske in the next game and held onto the lead for the set, losing just seven subsequent points on serve. She did need six set points to take the lead, though, as the American saved five in her own titanic service game at 5-2. 

In the second set, she bounced back from an early 2-0 deficit and denied Riske three further chances to lead 3-1. Losing serve in the second set snapped a streak of 24 consecutive holds for Osaka in the tournament, but she'd face no further adversity on serve. Later, Osaka broke for a 4-2 lead from a 40-15 down, and hit 40 winners in the match in total.

"She just fought for every point," Osaka said. "Also, I know her serve speed isn't that fast, like I was watching it every time I got aced. But it's kind of hard for me to read her serve, so I think that that was working really well for her, or it's just another day in the office for her. Yeah, I think her serve was really good.

"I also think normally I can kind of overpower people, but she was on the forehand, slapping it back in an odd way that made it kind of hard for me to hit away from her. That's what I knew I needed to do in order to beat her in the match. It kind of just felt like she had answers for some of the things that I was doing, so we were both adjusting from there."

Osaka is now 25-18 all-time against American players and 3-1 this year. 

Another American awaits: Standing between Osaka and her first semifinal berth in Miami is Australian Open finalist Danielle Collins, who Monday was a winner against Ons Jabeur. Osaka hasn't dropped a set against Collins in two prior meetings, but they haven't played in three years. 

More from Miami: Collins overpowers Jabeur, Saville saves match point to reach Miami QFs

Bencic eases past Sasnovich for first Miami quarterfinals

Seven years ago, Belinda Bencic made the fourth round in her main-draw debut in Miami, but in four subsequent appearances, only won one match combined. With a 6-2, 6-3 win over Aliaksandra Sasnovich, she's through to the quarterfinals for the first time.

Highlights: Bencic def. Sasnovich

Bencic lost her only prior meeting with Sasnovich from a set up at the 2018 US Open, but was largely in command in the rematch. From 2-1 down, with a break, in the opener, Bencic won eight straight games, and steadied herself after Sasnovich erased a 3-0 deficit in the second set to 3-3. 

Bencic has lost just 14 games in six sets played so far and moves on to face wildcard Daria Saville of Australia.