How quickly things can change in the supercharged tennis landscape. Look no further than the Americans' performances last week at the Miami Open.

To paraphrase the old cliché, the news of the demise of U.S. tennis has been greatly exaggerated. Even without an in-form Serena Williams, the other American women -- whether Grand Slam champions or intriguing newcomers -- gave the country a sense of optimism as the first quarter of the season came to a close.

"Sloane [Stephens] showed that she steps up in the big stage with the US Open and now here [at the Miami Open]," men's winner John Isner said shortly after claiming his title. "I think she had gone through a losing streak, and she was telling everyone to relax. She was absolutely right about that."

Sloane Stephens was among five Americans who walked away from the Miami Open with winner's trophies. Aaron Gilbert/Icon Sportswire

Stephens wasn't the only one who had U.S. fans feeling depressed shortly after the first Grand Slam of the year -- and for many weeks thereafter. The nation's players got off to a start this year that could only be called ugly.

But that all changed at the final Miami Open played on Key Biscayne. Stephens and Isner prevailed, as did Mike and Bob Bryan in men's doubles, along with CoCo Vandeweghe, who, along with Australian Ashleigh Barty, won the women's doubles.

"It seems like something special is happening," Frances Tiafoe, who's just 20, said in Miami, where he logged upsets of Kyle Edmund and perennial Grand Slam contender Tomas Berdych. "It seems each and every week someone is breaking through or proving himself."

Tiafoe is a good example. He was struggling with a 1-4 record, trying to find his game at the start of the New York Open in mid-February. Buoyed by two wins there, Tiafoe went to Delray Beach and swept through a very tough draw to win his first ATP main-tour title. He's at a career-high ranking of No. 58.

"Delray taught me a lot." Tiafoe said. "I beat some quality players back-to-back-to-back [Juan Martin del Potro, Hyeon Chung and Denis Shapovalov], which I've never done. I've played so many matches in my career so far where I played unbelievable, came up just short. Now I'm feeling really comfortable when it gets tight. I actually embrace it; I want it."

It's welcome news because, at the beginning of the year, it seemed as if the only American players who "wanted it" were relative unknowns such as Tennys Sandgren, Bernarda Pera and Lauren Davis.

After two rounds of play at the Australian Open, U.S. players had a grand total of just 12 wins and 20 losses (the women were 6-11, the men an equally anemic 6-9). Only two men, Ryan Harrison and Sandgren, made it as far as the third round. Only three women did the same: Madison Keys, Davis and Pera.

The drought worsened as the weeks went on. Isner, 32, had exactly one ATP tour W at the start of the Miami Open. Stephens was a tepid 2-3. Jack Sock was 3-3, and his ranking dropping from No. 8 to its present No. 16.

This season, Keys posted just one match in the past two months and Vandeweghe still has just one singles tour win on her résumé.

But despite their struggles, the pendulum finally appears to be swinging the other way, with Isner, Tiafoe and Stephens leading the way. And let's not forget reliable Venus Williams; she's a respectable 7-2 since the tour left Australia.

The U.S. has nine men in the top 100, and only two of them (Isner and 30-year-old Sam Querrey) are 30 or older. Querrey is treading water at No. 14. But he has an explosive game that can go off at any time, plus a low-stress style that ought to hold up well into his 30s. Steve Johnson had just one tour win by mid-February, but he's in revival, and Harrison has been on an upward arc all year.

Jared Donaldson, 21, and Taylor Fritz, 20, have also ramped up their results since that dismal late winter period.

The U.S. has 15 women in the top 100 if you allow Pera to sneak into the head count at No. 101. Ten of them are 25 or under, led by Stephens and Keys. That's a good sign at a time when everyone is sensing great opportunity.

Three of the more intriguing players to watch in the coming weeks are CiCi Bellis, Danielle Collins and Amanda Anisimova.

Bellis had back-to-back wins over Keys and No. 5 Karolina Pliskova in Doha. Collins is a late-starting pro who insisted on finishing college and won the NCAA championship twice. She has a great deal of poise and a fearless game that bodes well for her future. Anisimova already has wins over former Wimbledon champ Petra Kvitova and dangerous staple Anastasia Pavlyuchenkova.

"The younger generation has arrived, finally," Martina Navratilova, an 18-time Grand Slam winner and Tennis Channel analyst, told ESPN.com. "It's happening on the ATP and the WTA, too."

It seems that a turnaround moment also arrived for U.S. players of all ages at the Miami Open, and not a minute too soon.