The decisive moment of much-awaited fourth round match between world No 1 Simona Halep and seven-time Australian Open champion Serena Williams came in the third set.

The Romanian had pushed the match into the decider after being blitzed 6-1 in the first set. The match was evenly poised in the third set. Williams had saved three break points and an extremely lucky net chord for Halep brought up the fifth deuce in the sixth game on the American’s serve.

The 37-year-old looked more rattled than she has in any match so far. “This is not fair,” she could be seen mouthing in frustration, her hands raised in the air. And then she hit a monster wide ace and followed a winner and a down-the-line winner to hold serve. She broke Halep’s serve in the very next game to then win the match on her serve.

This little moment in the big match showed yet again that no one responds to adversity like Serena Williams.

You throw her a curveball and she will thunder down a winner as only she can. That’s precisely what she did in what was the best match of her comeback from maternity break. Top seed Halep made made the 16th word work for every point in the last two sets but with her characteristic grit, Serena prevailed 6-1, 4-6, 6-4 to become the oldest ever woman to beat a world No 1.

It’s hard to believe now but the match started with 27-year-old Halep – who beat her sister Venus in the earlier round – on the front foot breaking Serena to love in the first game after committing a double fault. But then the real Serena showed up, winning seven straight games with 10 winners in the first set.

In an earlier article, we had explained why Halep will be toughest early test for Serena, something that she had not faced in her final runs at Wimbledon and US Open. And the 2018 runner-up lived up to the billing after she got over the initial train wreck of a first set.

“I felt like I was hit by the train,” Halep said after the match.

Credit where it is due, the world No 1 showed up in the second set and displayed a game worthy of the top-ranked player. With her supreme endurance and retrieving skills, she started to make a match out of it, staying in the point, returning with interest and forcing Serena to make errors. Side-to-side movement down the baseline has been one of the former world No 1’s weaknesses since her return and extending the rallies by hitting corner to corner showed that Halep had her plan straight.

Raised her game to the next level

But as she has time and again done, when the chips were down, Serena just rose to the occasion. In a gesture that will be recognised by all women, she piled her hair up in a bun before the third set began. That was a sign: she was rolling up her sleeves to prepare for the heavy lifting and nothing was going to stop her now.

At 37 and with 23 Grand Slam titles, she has more than enough experience of what is needed to elevate her level at the big moment. But on Monday, she did that with a resilience she has not often needed since her return to tennis.

Before this match, Serena had dropped a total of only nine games through three rounds. Halep also ended Serena’s 21-set Australian Open winning streak, that dated back to her 2017 title. But the all-time great kept up the streak that mattered (of winning the matches), thanks to how she wore down Halep, even when luck didn’t favour her.

The ratio of winners to unforced errors paints a picture of how Serena dug deep while raising her game: she committed 31 unforced errors overall to Halep’s 12 but dominated the winners-count 44 to 24.

“This is my job – to come out and play in front of you guys,” Serena told the crowd after her win.

“I’m such a fighter, I just never give up ... it’s definitely something that’s innate. I just work so hard for every point. And I just feel like it’s a miracle that I’m here, I get to do something that I enjoy.”

Unmatched hunger and drive

These words give you a good idea about the kind of hunger and drive Serena has for tennis, along with tanks of talent. She loves the grind, revels in the tough wins.

After childbirth and life-saving surgery, to be here and competing at her level is incredible. But to push the best player of 2018 to the extreme with her reserves of willpower as much as her racquet is the truer testament to what she is made of.

This is her first tournament since the US Open where controversy marred a one-sided final and the otherwise superlative tennis she had played in New York. In the quarters there, she had beaten Karolina Pliskova, her highest-ranked victim since her return.

The seventh seed is also her next opponent in Melbourne, but given how she fought it out against Halep, there is a good chance that she can clear the field as she moves to another Major, which will also give her the all-time record for most Grand Slams.

But more than the record quest, it’s her backs-to-the-wall tennis and enjoying every moment on the court that makes her such a dangerous opponent.