The unseeded Osaka defeated No. 22 Belinda Bencic 4-6, 6-3, 6-4 on Thursday in the Miami Open semifinals.
Medvedev dropped to second with a third-round loss to Gael Monfils at Indian Wells last week, but would have taken back the top spot from Serbia's Novak Djokovic had he defeated Hurkacz.
Ruud will compete in a hard court semi-final at this level for the first time after reaching the same stage on clay at the Masters 1000 events in Monte Carlo, Madrid and Rome.
The Russian held the No. 1 ranking briefly, lost it to Djokovic again about a week ago and is now closing in on capturing it again.
Indian challenge, thus, ended at the ATP/WTA tournaments.
Frequent partners since 2019, the Indo-Candian duo went down 2-6 1-6 to sixth seeds Wesley Koolhof of Netherlands and Great Britain's Neal Skupski.
Shaking off a slow start, the top-seeded Medvedev reached the quarterfinals of the Miami Open on Tuesday by defeating Jenson Brooksby of the U.S. 7-5, 6-1.
Osaka’s only other quarterfinal appearance in the last year was at an Australian Open warmup tournament in Melbourne in January.
The unseeded Indo-Canadian pair surprised Mektic and Pavic 6-3 7-6(3) in a second-round doubles match on Sunday.
Swiatek's ascension was clinched Friday night with a 6-2, 6-0 win over Viktorija Golubic of Switzerland in the second round of the Miami Open.
The former world No 1 is through to the third round at the Miami Open, easily handling 13th-seeded Angelique Kerber of Germany 6-2, 6-3 on Thursday.
Serbia's Novak Djokovic moved into the top spot of the rankings this week, bumping out reigning US Open champion Medvedev after a three-week stay following his third-round exit at Indian Wells.
Medvedev made quick work of his Czech opponent, finishing Machac off in just over an hour. The Russian won 80% of his first-serve points and saved the lone break point he faced.
The 20-time Grand Slam champion tweeted on March 9 that the Centers for Disease Control “confirmed the regulations won't be changing so I won't be able to play in the U.S.”
Indian Wells begins next week, and had she played it would have been Barty's first appearance there since 2019. The Miami Open, where Barty is the two-time defending champion, begins March 21.
Juan Martin del Potro sent his devoted fans home happy by powering into the ATP Miami Open quarter-finals with a 6-4, 6-2 triumph over Serbian Filip Krajinovic.
American Sloane Stephens had cause for a double celebration after beating Germany's Angelique Kerber 6-1, 6-2 to reach the WTA Miami Open semi-finals.