Tretiakov enjoyed two strong runs on the German track, while several of the other pre-competition favourites suffered a difficult first day of competition.

He is competing as part of the Bobsleigh Federation of Russia team at the World Championships, under restrictive conditions imposed by the Court of Arbitration for Sport ruling last December.

Under the two-year ban imposed on Russia for tampering with data from the Moscow Laboratory - halved from the four years proposed by the World Anti-Doping Agency - its athletes compete as neutrals, with altered uniform branding, and may not have the national anthem played at medal ceremonies.

The Russian national flag is also precluded from ceremonies, although flags including Russian colours are allowed.

Tretiakov achieved a combined time of 1min 53.30sec from his two competition runs today.

The Sochi 2014 gold medallist, who was stripped and then reinstated as Olympic champion after having a doping offence overturned by the Court of Arbitration for Sport, will hope to secure a second world title.

Tretiakov, the 2013 world champion, holds a narrow 0.04 advantage over 2020 junior world champion Felix Keisinger of Germany.

Defending world champion Christopher Grotheer, also of Germany, lies 0.06 off the race lead at the halfway mark.

There is a bigger gap to the remaining contenders, with Bobsleigh Federation of Russia’s Evgeniy Rukosuev lying fourth at 0.49 down.

Overall World Cup winner Martins Dukurs had a difficult opening day, with the Latvian star down in 14th place at 1.83 behind the leader.

Olympic silver medallist Jacqueline Lölling leads the women’s skeleton event following the first two runs of competition.

The German star achieved times of 58.39sec and 58.35 to finish the day with a combined total of 1:56.74.

She holds an 0.11 advantage over Elena Nikitina, with the Bobsleigh Federation of Russia athlete lying in second place.

Tina Hermann saw her title defence get off to a shaky start after recording only the 11th fastest time in the opening run.

Hermann was quickest in the second run, with the German cutting her deficit to 0.24 to Lölling.

Austria’s Janine Flock began as one of the favourites for the women’s title, with the 31-year-old having been crowned this season’s overall World Cup winner.

Flock’s challenge faded on the opening day, as she lies 2.25 off the pace in 14^th place.

The men's and women's skeleton competitions are scheduled to conclude tomorrow.