Norway's Therese Johaug won the women's 10 kilometre classic mass start at stage five of the Tour de Ski in Oberstdorf ©Getty Images

Norway’s Therese Johaug beat compatriot Ingvild Flugstad Østberg in the women’s 10 kilometres-classic mass start in Oberstdorf today to reduce her team-mate’s lead in the Tour de Ski to just 12.2 seconds.

Johaug’s time of 26min 37.6sec saw her finish 9.9 seconds clear of Østberg, leader of the overall tour standings after five stages on 1 hour 24min 37.2sec.

"It was really tough race," said Johaug.

"Ingvild had a great competition.

"She has been in a great shape and I knew I had attack on the last hill.

"I am happy to gain some seconds."

Referring to the last of the eight-race series at Val di Fiemme in Italy, Johaug added: "It will be a tough fight with her all the way to the top of Alpe Cermis."

Rounding off the podium was another Norwegian, Heidi Weng, 19.7 seconds off the pace.

Weng remains in third place in the overall tour standings, 2:33.1 behind Østberg.

Three races remain in the series with action set to resume on Friday (January 8) in Toblach, Italy, where individual races are scheduled to be held. 

Kazakhstan's Alexey Poltoranin came out on top in the men's 15km classic mass start
Kazakhstan's Alexey Poltoranin came out on top in the men's 15km classic mass start ©Getty Images

Meanwhile, in the equivalent men’s 15km race, Kazakhstan’s Alexey Poltoranin posted a time of 35:35.9 to win in a photo-finish ahead of Switzerland’s Dario Cologna by just 0.1 seconds.

Despite finishing 23rd, Norway’s Martin Johnsrud Sundby still leads the Tour de Ski on 2:15:16.6 after five of eight races, which also count towards the International Ski Federation Cross-Country World Cup.

Sundby is 47.2 seconds ahead of team-mate Petter Northug Jr, who was ninth on the day.

"I had a great race," said Poltoranin.

"I am happy; I am the first guy this winter to beat Martin in a distance race.

"I hope for top 10 in Toblach and I will fight for third place in the Tour de Ski."

Italy’s Francesco de Fabiani finished 0.6 seconds back in third place, meaning a Norwegian athlete was not represented on a distance World Cup podium for the first time this season.