Serena Williams won her first Grand Slam as a 17-year-old at the 1999 US Open. Bianca Andreescu, the 19-year-old making her US Open main draw debut, was born in 2000.

Now, the two will meet in an inter-generational 2019 US Open final in what will be a history-making clash, whichever way it goes.

Twenty years after her first, Williams is looking to equal Margaret Court’s record of most Majors at 24 while Andreescu could become the first player born in the 2000s to win a Grand Slam. Both outcomes will be incredible, both outcomes are completely possible.

Andreescu is fearless, with a 32-4 record and two titles this year despite a five-month injury layoff. She quite literally doesn’t know how to lose, but she has never been at this big a stage before.

First teen US Open semi-finalist in a decade, Bianca Andreescu builds on astonishing 2019

Williams is peerless, with 23 Major titles before giving birth and reaching four Slam finals after. She knows what it takes to decide a championship match, but she has stumbled so badly on her last three attempts that No 24 has become a mental block.

The two met in the Rogers Cup final last month – the last big hardcourt tournament before the US Open – but before we could savour the tennis, Williams had to retire while trailing 3-1 due to a back injury. Then the Canadian teenager, who had broken her early, consoled her saying she is a ‘beast.’

Now, the Canadian teen sensation will have to tame the very same beast she has grown up watching to win the title on her US Open main draw debut.

In a way, this final shouldn’t be happening. Williams’ US Open plans were in disarray after her tearful retirement while Andreescu, was sidelined with right shoulder injury for five months and pulled out of Cincinnati to rest after her Toronto triumph.

But the final of the last Grand Slam of the year may be decided by the one who is able to forget the occasion and play it like ‘any other match’. If both competitors bring their ‘A’ game on Saturday, we will have a cracker of a women’s final.

The two women almost have the same command on the tennis court: The powerful winners from both flanks, the ability to vary their game when needed, a good serve to dig them out of holes.

In their respective semi-finals on Thursday night, the straight sets scoreline doesn’t quite tell the full tale.

In the first semi-final, Williams looked set for a grind against counterpuncher Elina Svitolina after the first two games lasted 16 minutes. The American fought off six break points in the first set that lasts 44 minutes and then crushed the second to win 6-3, 6-1.

She played a very clever game against the younger fifth seed, changing the pace, hitting drop shots and even going for the serve-and-volley. She won 11 of 16 net points, had six aces and 34 winners to 20 unforced errors, it was a complete performance.

While Williams displayed all-round flair, Andreescu showed grit in the second semi-final.

In the first set against 12th seed Belinda Bencic, she saved six break points including a set point, before dominating the tiebreak. In the second, she fought back from 5-2 down and then dialled up her winners to win 7-6(3), 7-5.

Bencic got annoyed and made errors but the four consecutive breaks showed the never-say-die quality of the Canadian’s game. She was clutch in crucial moments and played the big points with an ease that belied her age. The overall numbers painted a good picture: 9/13 net points won, 40 winners to 38 errors, 7 aces to 9 double faults. In fact, her winner statistics have been phenomenal through the tournament.

The commentators said that the teenager is a player who doesn’t know to lose, and it is close to the truth. With 7-0 against WTA Top 10, the ‘unknown quality’ has not really tasted defeat that can dim her confidence. She hasn’t lost a completed match since March and won two Premier Mandatory titles.

For Williams, though, final losses have become quite the bizarre reality.

For a player who won 21 of her first 25 Grand Slam finals, she has suddenly become the player who lost her last three. Her current final losing streak is the longest of her career and just the third time that she has lost consecutive title matches.

After her second straight lopsided loss in the Wimbledon final, Williams admitted that she needs to learn to win finals again. Getting to the final hasn’t really been an issue for the 37-year-old, but something has stopped her from taking that last step.

Against a teenager, it might not necessarily be easier for her than against Simona Halep. With an 18-year age difference between the two, this is the largest age gap in a final in the history of the Open era.

But what Andreescu lacks in terms of big-match experience, she makes up with her unmatched momentum. Her strong and swift game can match Williams’ power and with her angled winners, she can disturb the American’s rhythm.

On the other hand, Bencic exposed the chinks in her serve that can be exploited: her second serve in the first set won just 27% points and with Williams’ return game, she can blast any loose serve.

Wozniacki compared her game to Kim Clijsters and we know the superior record Williams had.

In a way, Andreescu has to just learn from her final opponent. Williams beat Clijsters, Monica Seles, Lindsay Davenport and Martina Hingis en route her first Major title at the 1999 US Open. The confidence and fearlessness the then 17-year-old showed is what the 19-year-old is showing 2019.

After her quarter-final win, she screamed “Is this real life?”

After making her way in the final, she didn’t question it, she just believed.

If she goes on to the win the last Slam of 2019, nobody would find it hard to believe. But if Serena Williams wins an incredible 25th Major, it will be an unbelievable achievement for 37-year-old.