Bianca Andreescu roared back from a set down to take out No.7 seed Maria Sakkari 5-7, 6-3, 6-4 to advance to the Miami Open third round.

Here are the key takeaways from the former US Open champion's second three-set win in as many rounds this week so far.

Andreescu and Sakkari can always be counted on to go long

Andreescu and Sakkari have now played three times, and all three have been extended three-setters that have featured a number of twists and turns. This result reprised their previous meeting in Miami, when the Canadian triumphed 7-6(7), 3-6, 7-6(4) in the 2021 semifinals from 4-2 down in the decider before retiring against Ashleigh Barty in the final. Sakkari got her revenge 6-7(2), 7-6(6), 6-3 in the fourth round of the US Open in the same year.

Photos: 2023's three-hour matches

This match, the first of their rivalry not to feature a tiebreak, was the second-longest at 3 hours and 4 minutes in length -- still some way short of the 3-hour, 30-minute US Open barnburner.

Andreescu was clutch in the tightest moments

The former World No.5's defeat of Emma Raducanu in the first round was characterised by her strong play on big points, and that quality shone through again. Notably, serving at 4-2 in the second set she held her nerve through six deuces to consolidate her break lead. She also got the better of a three-break exchange that opened the decider, nailing key return winners to capture the Sakkari serve twice.

Andreescu played a cleaner match than the Greek, landing 21 winners to Sakkari's 26 and keeping her unforced error count to 31 compared to Sakkari's 54. Sakkari's tally grew throughout the first half of the third set as she struggled for rhythm, though she delivered a valiant late-stage fightback attempt from 4-1 down.

Andreescu also held her nerve as Sakkari clung on. Serving for the win, she missed her first two match points and had to save a break point before finding her strongest serves to seal victory.

"I felt like I was on my heels a lot of the time during the match, but I made every ball," said Andreescu. "I fought to the end, and I think I played the important points just a little bit better today. But, yeah, it could have gone either way today."

Andreescu's comeback is looking up again

Miami marks the completion of a full year's worth of tournaments since Andreescu returned to the tour in Stuttgart last April, following a six-month mental health hiatus. Her record since coming back is 28-19 so far, and she has reached No.31 in the rankings (potentially returning to the Top 30 after Miami).

Andreescu has now notched three Top 10 wins in her comeback: her victory over Sakkari followed wins over Danielle Collins in Madrid and Daria Kasatkina in Toronto.

"It's just another step in gaining most of my confidence back," she said. "I'm feeling really good on the court. I'm trying to be as fearless as I can be. It's not always easy, but I feel like I'm getting there, and wins like this obviously help with that because at this point I think it's just me getting matches in and playing tough rounds like this and knowing I can win."

But maybe the most positive aspect of Andreescu's Miami run so far is her health. A shoulder injury forced her to retire in the Hua Hin semifinals at the start of February, and visibly affected her during that month's Middle East swing. But she has survived a punishing draw with two three-set wins.

"I'm happy I didn't cramp!" she joked in the on-court interview after beating Sakkari.

The tough draw doesn't stop here: Andreescu will next face 2020 Australian Open champion Sofia Kenin, who defeated No.28 seed Anhelina Kalinina 6-3, 6-4, as she bids to reach the fourth round in Miami for the third time in as many appearances. Andreescu leads their pro head-to-head 3-1, but the pair have not played since either won their first major title. Their last meeting was in the 2019 Toronto semifinals, with Andreescu winning 6-4, 7-6(5).

"I think she's playing great tennis," said Andreescu. "I've watched a few of her matches this year. I know that she might not be doing as well as she's hoping, but same with me. So I think it's going to be an interesting matchup."