Bianca Andreescu had to go the distance against Irina-Camelia Begu of Romania before winning through, 6-3 4-6 7-6(5), to set up a semi-final against Marie Bouzkova in the Phillip Island Trophy, in the last quarter-final played on Wednesday.
The No 2 seed from Canada, who won 2019 US Open before injury kept her off the WTA Tour for 15 months, is still ranked No 9 in the world and is making her comeback in Melbourne.
After losing last week, The 20-year-old entered the new WTA Tour 250 event for early losers at the ongoing Australian Open after being ousted in the second round of the Grand Slam last week.
She received a bye in the first round of the Phillip Island Trophy before topping the 85th-ranked Madison Brengle in the second round and the 83rd-ranked Zarina Diyas in the round of 16.
Now she has added Begu, who is ranked 74 in the world to her growing list of wins that now read 4-1 for 2021.
In her latest match, Andreescu toughed it out over Begu in 2 hours and 25 minutes in the fourth 3-setter the pair have played in as many meetings, and the 3rd in a row that the Canadian has won.
She needed to come from a break down in the deciding set, however, to quell the Romanian in a match that ebbed and flowed in an unpredictable contest.
Andreescu came from an early break down to take 6 of the last 7 games of the first set, before Begu hit back to take a 5-1 second-set lead.
That nearly wasn’t enough as Andreescu responded by taking 13 of the next 16 points to erode the World No 74’s lead, but Begu managed to serve it out at the second time of asking to force a decider.
Begu got the first break of the third set and went up 2-0, but was broken back and, a couple of games later, a second break of the Romanian’s serve gave Andreescu the chance to serve out the match at 5-3.
This time, however, Andreescu could not serve out the match, yelling afterwards in frustration: “Play tennis!”
Ultimately, the Canadian’s fortitude in the biggest moments paid off, despite striking fewer winners, 21 to 22, and making more unforced errors, 44 to 40, than Begu.
At 5-5 in the deciding tiebreak it was a Begu forehand that sailed wide before Andreescu nailed a forehand winner down the line to clinch victory.
In the last four, Andreescu will face No 13 seed Marie Bouzkova from the Czech Republic, who came through 6-3 4-6 6-2 over Jil Teichmann in a high-quality and tightly contested match that took an unfortunate turn when Teichmann went over on her ankle at 2-3 in the third set.
Although the Swiss World No 58 resumed play following medical treatment, the remainder of the encounter was one-way traffic for Bouzkova, who sealed her first semi-final place since making the Monterrey final last March.
In the top half of the draw, matters were simpler for No 8 seed Danielle Collins from the USA and former World No.10 Daria Kasatkina from Russia.
Collins dismissed No 16 seed Rebecca Peterson, 6-1 6-2, while Kasatkina upset No 4 seed Petra Martic, 6-0 6-4, to set up an intriguing stylistic contrast in the semi-finals.

Danielle Collins easily dispatched Rebecca Peterson to reach the semi-finals where she plays Daria Kasatkina, who upset Petra Martic, the 4th seed, on Wednesday