Norway's Johannes Thingnes Boe came out of isolation to deliver a blistering skiing display that brought his team back from the dead as they claimed victory in a thrilling sprint finish to win the gold medal in Saturday's 4x6-kilometer mixed relay.

France took silver, nine-tenths of a second behind the Norwegians, with the Russian Olympic Committee team winning bronze, a further six-tenths of a second off the pace, but it was Boe's brilliance that won the day.

Allowed to train, but forced to isolate from his teammates due to him being a possible close contact of a COVID case, Boe laughed off the restrictions as he celebrated the win.

"I can train, and I can win gold for Norway," a beaming Boe told reporters, his second Olympic title after winning the 20-km race at Pyeongchang 2018.

The close-contact restrictions were still in place as the winners were presented with their bouquets of flowers, Boe standing apart from his team at the ceremony, just as he had stood out from the field half an hour earlier.

His brilliance allowed Norway to overcome some minor disasters as they seemed to set themselves up for victory only to seemingly throw the chance away before Boe rescued them at the end.

Norway's Marte Olsbu Roeiseland survived trouble with her ski poles and rifle to build a lead of 21 seconds over the Italians at the first changeover, but Tiril Eckhoff let that slip with some wayward shots to allow Italy's Dorothea Wierer to cruise into first place.

In a topsy-turvy race, France held the advantage at the second changeover, closely followed by the Italians and Swedes as darkness closed in on the National Biathlon Center.

With the flags fluttering in all directions in the swirling breeze, all three nations shot perfectly from the prone position to leave France's Emilien Jacquelin with a 22.7-second lead entering his second lap and the Norwegians far down the field.

Despite freezing temperatures, a pressure-cooker atmosphere was building inside the Biathlon Center and it exploded in the form of Boe as he took over from his brother Tarjei for the final lap.

The 28-year-old Norwegian powerhouse closed the gap and then decided to bide his time before accelerating into the home stretch to blast past his opponents, triumphantly punching the air as he crossed the line.