Serena Williams was broken in her first service game by 19th seed Anastasija Sevastova. The US Open semi-finals are known to be a strange stumbling block for the former world No 1. In 2009, she lost to Kim Clijsters. In 2015, she went down to an unseeded Roberta Vinci, falling agonisingly short of a Calendar Slam. In 2016, she was ousted by Karolina Pliskova.

What would Serena do?

Well, she did what she best known for – lights-out tennis. She went on to beat the Latvian first-time Grand Slam semi-finalist 6-3, 6-0, winning 12 of 13 games.

Naomi Osaka faced four points in her second service game. The 20-year-old was in her first Major semi-final and was facing last year’s runner-up Madison Keys, who has beaten her three times before this.

What would Osaka do?

By her own admission, when she finds herself in trouble while serving she usually goes by a simple rule – “What would Serena do?”

In this case, Osaka mixed up her serve, held her nerve and played exceedingly superlative tennis to reach her first Grand Slam final with a 6-2, 6-4 win.

But in her next match, if Osaka finds herself in a similar tough spot, she might not be able to follow her mantra. Because her idol, Serena Williams, will be on the other side of the net.

While she has never bothered to hide or tone down her admiration for the 36-year-old American off-court, she has not let it affect her on-court either.

The last time the two had met, in the first round of the Miami Masters in March this year, the Japanese youngster had triumphed 6-3, 6-2. It is after that match that the reigning Indian Wells champion had said: “This is going to be really bad. Sometimes when I’m in a really important position, when I’m serving, I’m like, ‘What would Serena do?’”

On Thursday night, she saved an incredible 13 break points. When Tom Rinaldi asked her what was going on in her head as she held serve, she made a trademark candid confession.

“This is going to sound really bad, but I was just thinking, ‘I really want to play Serena.’”

Why?

“Because she’s Serena. Like, what do you mean?”

Contrasting semi-finals, a mouth-watering final

The straight-sets scoreline would suggest that both Serena and Osaka reached the finals with a straightforward win. But both their wins were contrasting.

Serena switched on her attack mode after going 0-2 down and overpowered Sevastova. She used a different trick from her toolbox, coming to the net and volleying for winners, scoring 24 out of her 28 net points.

Osaka, on the other hand, faced more resistance. While Keys sent down a barrage of good shots, interspersed with unforced errors, Osaka’s task was to control both her nerves and shots to make sure she didn’t make similar errors. Like Serena, she plays a brand of heavy-duty tennis. But against the 2017 runner-up, she tempered that with guile and variety to never let the American get more than a toehold in the game.

The story of 13 squandered break points will say that it was Keys who couldn’t rise to the challenge. But it was Osaka who didn’t let her, serving brave and versatile and powerful and precise at the same time. She committed just one double fault even as she kept telling herself to not mess her second serve, and managed to win 58% of her second serves, making sure she didn’t lose her serve once.

The 12-minute blockbuster game

The best example of what set Osaka apart in the semi-final was the second game of the second set. Despite leading a set and break, the Japanese player could not rest easy. Last year at the US Open, Keys had come back from 1-5 down in the third set to beat her.

In that 12-minute second game, Keys held six break points. It was a make-or-break moment of sorts as they thundered powerful baselines rallies and deft net shots.

There was a 17-shot rally that was a highlights reel in itself and through the long game with eight deuces, Keys and Osaka traded booming forehands and cracked superb winners. Osaka threaded the needle at the net, Keys fired an unreturnable forehand. Keys slipped and fell, Osaka sent down a monster ace.

By the end of it, Osaka emerged unscathed and held, all but ending Keys’s resistance.

At 3-4 down in the second set, Keys got another break chance, but Osaka responded with a superbly controlled point to hit a winner after coming in to the net. Keys kept leaking errors – 32 in the match – but her groundstrokes put Osaka’s serve under pressure. But the young Japanese, kept a positive mind-set and cracked a brilliant backhand to hold. From then on, it was a formality.

A love hold from Keys later, the 20-year-old was serving for a place in her first Grand Slam final, against her idol Serena, a scenario she had dreamed of for years.

Two points away, she was talking to herself, telling herself that she was almost there. And her swift, smart play gave her the match point and a win – on an error, of course. But like the match, she was composed in the aftermath as well. No tears like after the win against Aryna Sabalenka – she was affected by people making fun of her emotions – but she choked up as she spoke to Tom Rinaldi.

“I love you, mom. I love you, Serena. I love everybody,” an ecstatic Osaka proclaimed.

But love and admiration will take a backseat when the first Japanese woman to reach a Grand Slam final takes on her idol on Saturday. Osaka will channelise her inner Serena and hope to once again get the better of the American.

Whether it will be a record 24th Grand Slam for Serena or a historic first for Osaka, it is sure to be firecracker of a women’s singles final.