In January, Danielle Collins announced that 2024 would be her final season on tour following a second-round loss at the Australian Open.

On Saturday, less than three months later, she won the biggest title of her career.

Playing in her home state of Florida, the 30-year-old Collins entered the Miami Open unseeded and ranked No. 53 in the world. But after she dropped the first set in her opening-round match against fellow American Bernarda Pera, Collins was virtually unstoppable. She rolled through the draw -- never dropping more than five total games in a match -- into the final.

She faced No. 4 seed and 2022 Wimbledon champion Elena Rybakina in the final, in front of a packed crowd that included Andre Agassi, one of her childhood idols. Collins capped off her incredible fortnight with yet another dominant performance, winning the match 7-5, 6-3.

"I used to beg my dad to take me here and he said, 'You can go when you play in the tournament.'"Danielle Collins just WON the tournament!#MiamiOpen pic.twitter.com/s2bN4gvGIV— wta () March 30, 2024

It marked the first 1000-level title for Collins and her first WTA trophy since 2021. She became the lowest-ranked women's champion in tournament history -- and her ranking has now skyrocketed to No. 22 as she heads to South Carolina for this week's Charleston Open.

While it would be understandable to think Collins might now be reconsidering her decision to retire at year's end, she has continued to shut down such speculation, citing her challenges with endometriosis and hopes to start a family. But she has said that the looming finish line has given her extra motivation.

"I really think part of the reason why I played so well and did a good job today was because I had that mentality of, like, I'm going to enjoy every minute of this," Collins told reporters after her victory. "This is my last year, this is my last season, and these are some of my final events. I want to remember these moments."

Knowing just how good Collins can be when she's at her best, the rest of her farewell tour could certainly be one to remember.

Here's what else you might have missed from around the tennis world last week:

The Sinner Era continues

It's been a milestone season for Jannik Sinner. The 22-year-old won his first major at the Australian Open, followed it up with a trophy at Rotterdam, and on Sunday won the Miami Open title with an impressive 6-1, 6-3 victory in just 74 minutes over Grigor Dimitrov.

Sinner, who stunned Daniil Medvedev with a 6-1, 6-2 result in the semifinals, is now ranked a new career-high of No. 2 in the world, surpassing Carlos Alcaraz and behind only Novak Djokovic. Sinner is the first Italian man to achieve the ranking and to have won multiple Masters 1000-level titles, having previously hoisted the trophy in Toronto last summer.

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"Being No. 2, it's an amazing feeling," Sinner said during his postmatch news conference. "I never thought to come to this point. ... I'm just enjoying every moment. These are special days winning a tournament. Doesn't matter what kind of tournament, it's a special day. It means a lot to me."

Sinner now holds a staggering 21-1 record on the year, and even his peers couldn't hide their admiration after Sunday's match. Alcaraz posted several emojis on Sinner's post about the win, including fire and an up arrow, and Dimitrov heaped on praise during his own news conference.

"I think at the moment clearly Jannik is playing outstanding tennis," Dimitrov said. "There is nothing to say to that. You see how focused he is, how determined he is, the way he's hitting his shots, there is zero doubt, so a lot of that level, it's extremely high up ...

"Can he play any better? I don't know. He's the one to show that. But at the moment that he's been able to really put so many matches back to back with the same level, so all credit goes to him. And he is the best player right now in the world."

It's still Serena's world

Sure, Collins and Sinner were the big winners in Miami, but it was a special guest during the men's semifinal matches on Friday that stole the show.

That of course would be 23-time major champion -- and winner of eight Miami titles -- Serena Williams. After appearing on site to cheer on her sister Venus earlier in the tournament, Williams was back to support her longtime pal Dimitrov in his victory over Alexander Zverev, as well as watch Sinner in his win against Medvedev.

Dimitrov, who made his return to the top 10 on Monday for the first time since 2018, later told reporters he speaks to Williams "nearly" every day and called her continued support "humbling."

"It's friendship, man," Dimitrov said. "I think this is the best part. Tennis is tennis, but, you know, we are all living our dream right now. I think the real life begins after, and I think we have managed to be such good and close friends after so many years."

Iconic 🥹 #MiamiOpen pic.twitter.com/ITm24EElfG— Tennis TV () March 30, 2024

Williams also spent some time with Sinner on Friday after his win, and she too seemed in awe of his recent prowess.

"I wish I hit my forehand like that," she told Sinner. "Seriously, the racket speed, the power ... You're unbelievable. Congrats on Australia."

Unexpected champions

American duo Bethanie Mattek-Sands and Sofia Kenin had requested a wild card to play in the doubles draw in Miami but didn't get it, and they were not part of the draw when it first came out ahead of the tournament.

But they signed up as alternates and remained on site just in case there were any withdrawals. As luck would have it, a spot in the draw opened up when Marie Bouzkova and Sara Sorribes Tormo had to withdraw before play got underway.

And on Sunday, the pair concluded their unlikely trip to Miami by winning the tournament with a hard-fought, comeback victory over Gabriela Dabrowski and Erin Routliffe, for their second title of the season together.

Sofia Kenin & Bethanie Mattek-Sands weren't even supposed to be in the draw.But after a team withdrawal, they got in as alternates. Now they're champions 🏆Tennis! | | #MiamiOpen pic.twitter.com/ytkC74LNzS— wta () March 31, 2024

"Obviously we were bummed when we saw the draw and we weren't in, but at some point you got to let that go and be like, the universe has my back," Mattek-Sands told WTA Insider on Sunday. "I'm going to step forward through that, I'm going to go through my same routines and I think that's more how you create your luck.

"You don't let the bad luck get to you and change how you go about your day, change how you think about yourself and change what you think about the world around you. And if you can sort of keep that, you'll have all the luck in the world."

That philosophy certainly seemed to have been true in Miami, as the 39-year-old Mattek-Sands won the 30th doubles title of her career.

On the men's side, reigning Australian Open champions Rohan Bopanna and Matthew Ebden won the doubles trophy on Saturday for their second 1000 title together. With the victory, the 44-year-old Bopanna broke his own record as the oldest 1000-level winner in ATP history.

Coaching change for Djokovic

Djokovic withdrew from Miami ahead of the tournament, citing the need to balance his "private and professional schedule," but that didn't stop the world No. 1 from making headlines during the event.

On Wednesday, Djokovic announced he was parting ways with longtime coach Goran Ivanisevic in an Instagram post. The pair had begun working together in 2018 and had won 12 major titles in that span.

"Goran and I decided to stop working together a few days ago," Djokovic wrote. "Our on-court chemistry had its ups and downs, but our friendship was always rock solid."

Djokovic also wrote about their never-ending Parchisi tournament, and ended his message with kind words, calling Ivanisevic "Sefinjo" (the Serbian word for "Boss").

"Thanks for everything my friend. Love you."

Since their split, Djokovic has been seen training ahead of the clay season with retired Serbian player Nenad Zimonjic in Belgrade, but he has yet to announce the hiring of a new coach. During a screening of a documentary about Croatian tennis trailblazer Nikola Pilic on Thursday, Djokovic seemed uncertain on whether he would be formally adding anyone in the role to his team.

"I still don't have a clear idea who a new coach would be, or whether there will be one at all," Djokovic said, according to the Daily Express. "I've had coaches since I was a kid, now I am trying to feel by myself what I need, what I feel most comfortable with."

Djokovic, who has a 6-2 record this season in two events, is next expected to play in Monte Carlo later this month.