The Norwegian, who won Olympic gold in the 4x5km relay at Vancouver 2010, clocked 41 min 21.6 sec on the Swiss course as she bids to recapture the title she won in 2014.

She has climbed to the top of the Tour de Ski standings after two events as compatriot Maiken Caspersen Falla, the winner of yesterday's opening sprint race, opted to skip the 15km.

With all eight Tour de Ski races also counting towards the overall International Ski Federation (FIS) Cross-Country World Cup, sprint specialist Falla, the Sochi 2014 Olympic champion in the discipline, has opted to preserve energy as she bids to top the sprint standings come the end of the season.

Johaug led home an all Norwegian podium as Ingvild Flugstad Østberg finished second, 37.9 sec adrift, with Heidi Weng third and 1:16.2 off the pace.

The 27-year-old has now won seven World Cup races this season and heads the overall standings with 721 points, ahead of  Østberg who has 632.

Sweden's Stina Nilsson is third but is way back on 484 points.

Østberg was the Tour de Ski leader at the start following Falla's withdrawal, and was 45 seconds in front of Johaug.

However, Johaug was able to gain bonus seconds on the course and she now has a 4.5 sec lead over Østberg in the Tour de Ski standings.

Weng is third, 1:45.2 shy of the leader's time.

"I am really satisfied with today," said Johaug, the 2013/14 World Cup winner.

"I had a good feeling from the beginning of the competition.

"I did not plan to get the gap so early but I felt really strong.

"I kept the focus on the technique and managed to ski away from the other girls.

"I had also perfect skis.

"It was a good day in Lenzerheide."

Meanwhile, Martin Johnsrud Sundby won the men's 30km mass start event to ensure that Norwegians lead both Tour de Ski events.

The 31-year-old, the winner of the last two editions, claimed his sixth World Cup win of the campaign in a time of 1:14.48.3.

As with the women's race, Norway swept the podium with Petter Northug finishing second, 34.6 sec back, while Didrik Tønseth came home third, 35.1 sec behind.

Italian sprint specialist Federico Pellegrino, who won yesterday's opening 1.5km event to top the early Tour de Ski standings, finished 63rd today and has drifted out of overall contention.

Sundby's Tour de Ski lead is 1:18 over Northug, with Tønseth third, 1:30 behind.

"I felt tired from the start and still could feel yesterday’s sprint," said Sundby, who has won the last two overall World Cup crowns.

"I needed a couple of laps to get in the rhythm.

"I could feel the altitude.

"The race was as tough as I had expected.

"I have a good margin on Petter but that can easily disappear in Oberstdorf.

"The Tour has just begun."

Sundby, who has now won six races this season, has a commanding overall World Cup lead with 778 points on top of the table.

Closest challenger Northug has 453 while another Norwegian, Finn Hågen Krogh, is third with 352.

The Lenzerheide leg of the Tour de Ski concludes tomorrow with a 10km pursuit for the men and a 5km pursuit for the women.