US Open: Andy Murray vs Matteo Berrettini headlines Day 5
Murray has beaten Francisco Cerundolo and Emiliano Nava on his way to the last 32 (Getty Images)

This year's US Open hasn't been short of shocks, surprises and drama.

And, two of the sport's legends Andy Murray and Serena Williams will be back in action for Friday's play.

Both have breathed new life into this year's tournament, giving a casual throwback to years gone by when both used to sweep their opponents off the court.

It is what took both to the pinnacle of the sport, becoming world number one on the men's and women's circuits respectively.

Andy Murray vs Matteo Berrettini

Play on Arthur Ashe Stadium sees Murray enjoying his best form since a career-saving hip surgery taking on the man that beat him in his last ATP Tour title final.

Matteo Berrettini, of course, denied Murray another grass-court title in the final of Stuttgart back in June.

The Italian hasn't looked his best though over the American hard-court summer, with opening-round defeats during the Canadian Open to eventual winner Pablo Carreño Busta, and to Frances Tiafoe in Cinccinati.

But having missed Wimbledon due to Covid, Berrettini will be eyeing a deep run in New York, making this the ultimate test of Murray's newfound confidence and fitness.

Madison Keys vs Coco Gauff

The past takes on the future as the two Americans lock horns.

It was Madison Keys who famously made the final five years ago in 2017, before falling short to another American in Sloane Stephens.

Keys is one of a small cluster of players to have beaten world number one Iga Świątek this year.

The 27-year-old will be the underdog in this match-up, though, considering the form off Gauff.

The 18-year-old star reached the final of the French Open, losing convincingly to Świątek convincingly, but will no doubt be keen to impress at her own Grand Slam.

The youngster is often vocal about her admiration for idol Serena, who herself won her first Slam in New York.

So expect to see a pumped up Gauff in this clash.

Serena Williams vs Ajla Tomljanović

The 23-time Grand Slam champion overcame the odds to stun world number two Anett Kontaveit on Wednesday night.

40-year-old Serena seems to be riding high on the pre-retirement party atmosphere and soaking it all up.

The manner of that victory showed that the six-time US Open champion can still beat the best players in the world on her day.

However, Croatian born Australian Ajla Tomljanović is the younger of the two, and will be fresher given Serena's doubles commitments with sister Venus.

But with the Big Apple all behind their icon and attempting to push her onto more battles this fortnight, it is anyone's game.

Will Serena's bid for a record-equalling 24th Grand Slam title remain alive on Friday night? The tennis world holds it's breathe.