INDIAN WELLS, Calif. — Nearly a month after Emma Raducanu and Leylah Fernandez faced off in perhaps the most unexpected Grand Slam singles final, they returned to action as headliners.

Neither teenager had played in the Indian Wells Tennis Garden until this year, but they were front and center on Friday, anchoring the night-session schedule in their singles debuts at the BNP Paribas Open.

Raducanu, the big-surprise U.S. Open champion, was assigned to Stadium 1, the biggest showplace of the tournament. Fernandez, the Open runner-up, was assigned to Stadium 2, the second biggest showplace of the tournament.

Both faced older and more experienced opponents. Both had the crowd behind them from the start, even if there were empty seats galore in both stadiums.

Canceled in 2020 because of the coronavirus pandemic and postponed again this year from its customary dates in March, the event is expected to have fewer spectators than usual this October.

The scene still looked and sounded familiar on Friday night. The restaurants on site remain largely the same, including the Nobu outlet inside Stadium 2. The rock band that is led by American doubles stars Mike and Bob Bryan performed, as usual, on the main stage.

But the Bryans are now retirees after jointly ending their playing career last year, and other major stars are missing from Indian Wells altogether.

Novak Djokovic, Roger Federer, Rafael Nadal and Dominic Thiem are out of the men’s tournament. Serena and Venus Williams, and the No. 1 Ashleigh Barty and the No. 2 Aryna Sabalenka are out of the women’s event.

But some of the buzz remained as fans showed their proof of vaccination at the entry gates and walked on site to get a look at Raducanu and Fernandez.

Only Fernandez, a left-handed Canadian, made the most of the occasion: mixing full-cut groundstrokes with deft backhand drop shots and well-timed excursions to the net to defeat Alizé Cornet 6-2, 6-3.

It was a performance brimming with the sort of big-point resolve and all-court sparkle that Fernandez displayed on her way to the final in New York.

Raducanu could not make the same smooth transition. Though she won the first six points of her match against Aliaksandra Sasnovich, that was no hint of things to come. The sorts of shots that Raducanu routinely hit for winners during the Open — sharply angled quick-strike returns and swing volleys — often struck the tape or landed just long.

Though it initially seemed a pity that her much-anticipated return to competition was taking place in the middle of the night in London, perhaps it was for the best.

She did not hide her disappointment during her 6-2, 6-4 defeat, gesticulating and twisting away as the unforced errors piled up. Raducanu offered only a brief and subdued wave to the public as she exited the court after playing for one hour and 25 minutes.

“Everyone can beat everyone,” the 100th-ranked Sasnovich concluded.

It is hard to argue at this stage in women’s tennis. Raducanu did her part to prove it in New York, becoming the first qualifier in tennis history to win a Grand Slam singles title and doing so without losing a set in only her second major tournament appearance.

But she dropped two sets rather quickly to Sasnovich, a 27-year-old Belarusian from Minsk who bolstered her thesis about women’s tennis parity by pointing out that she had lost in the first round of this year’s U.S. Open.

“So, a little bit different you see,” she said, comparing her result to Raducanu’s.

Their last few weeks have been different as well, with Raducanu making two red-carpet appearances and returning to London as a superstar in need of a police escort from the airport to her home. That came only two months after she finished her high school exams and became a full-time tennis professional.

In an interview this week, Raducanu said that the last few weeks had been an “out-of-body experience,” as if she were “watching it happen” to herself.

She has made some tough calls, choosing last month not to continue working with the coach Andrew Richardson, a surprising move considering her breakthrough in New York. Raducanu has explained that she wants a coach with more experience at the top of the game. One logical candidate is Carlos Rodriguez, who coached the Grand Slam champions Justine Henin of Belgium and Li Na of China. Li’s longtime agent is Max Eisenbud, who also represents Raducanu.

“I think it’s going to take me time to adjust really to what’s going on,” Raducanu said after Friday’s defeat. “I mean, I’m still so new to everything. Like the experiences that I’m going through right now, even though I might not feel 100 percent amazing right now, I know they’re for the greater good.”

Raducanu added: “That’s the lesson I think, that you can easily get sucked into being so focused on the result and getting disappointed. I mean, I’m 18 years old. I need to cut myself some slack.”

That seems wise. Friday’s letdown was not a huge surprise. Sasnovich, like many WTA players, is more dangerous than her ranking suggests. Raducanu is just getting started on tour. The playing conditions in Indian Wells are also far different than in New York where the ball bounces lower and winners are generally easier to produce.

But Fernandez managed to thrive in both settings. Her heavy spin, particularly on the forehand side, gives her a greater margin of error. She also may have benefited from playing and winning a doubles match with the American teenager Coco Gauff on Thursday that helped Fernandez adjust to the court speed.

Unlike Raducanu, Fernandez has not changed her support team since the Open. Her fitness trainer, Duglas Cordero, sat next to her mother in the stands and frequently jumped to his feet when Fernandez won a point, just as he did in New York. Fernandez even kept her outfit the same, while Raducanu arrived on court in a new, predominately white ensemble.

Her rituals have not changed either: practice strokes and jogging in place between points; right fist clenched after success.

She had plenty on Friday. She was opportunistic and on target against Cornet, a Frenchwoman who has the baseline skills to extend rallies and matches.

“It does give me a lot of confidence, because Alizé, she’s a very tough opponent,” Fernandez said. “She fights for every point. I’ve practiced with her, too. We’ve had some tough practice matches. I knew that today was going to be hard.”

The third round should be tougher. Fernandez’s next opponent, Anastasia Pavlyuchenkova of Russia, was in fine form on Friday as she dominated the powerful American Madison Keys.

But at least Fernandez has more tennis to play in Indian Wells — perhaps much more tennis. Raducanu, after her first visit to the California desert, must now make the long journey back to Europe to play indoor events and continue the adaptation process.

Fernandez and Raducanu will long be linked for their all-teenager, out-of-the-blue final in New York. For now, their paths will diverge.