The 177 kilometres stage, starting in Nice, was expected to be pivotal in the overall classification in the UCI WorldTour event due to the route boasting several steep climbs.

A group of seven riders, including The Netherlands’ Niki Terpstra and the French duo Sylvain Chavanel and Cyril Gautier, broke away after 25km of the race but could not hold off the main contenders for the race win.

The key climb of the race came at 12km to go, with Team Sky setting a strong pace as the peloton tackled the Cote de Duranus, which saw race leader Michael Matthews of Australia slip out of the back of the lead group.

Poland’s Rafal Majka then hit the front of the race and provided an opportunity for his Spanish team-mate Alberto Contador to launch two attacks in the final five kilometres.

Thomas and his fellow Team Sky rider Sergio Henao of Colombia stayed with Contador, along with Zakarin and Australia’s Richie Porte, the defending Paris-Nice champion.

Contador and Thomas attempted to move clear for the stage win inside the final kilometre, but it was Zakarin, who served a two-year doping ban between 2009 and 2011, who came through to claim the victory in 4 hours 45min 11sec.

Team Sky’s Thomas was awarded the same time as the stage winner after ending narrowly adrift,

It was enough to give him the overall lead and Welshman will start tomorrow’s final stage 15 seconds clear of Contador.

“I know the roads well and they're hard racing roads and a lot more climbing to come,” Thomas said afterwards.

“It's by no means finished, Contador is a pretty good bike rider and Richie and Zakarin too.

“They’ve won huge races, there's still a hell of a long way to go and hopefully we can defend the jersey.”

The final stage will again see the peloton tackle several climbs, with the route beginning and ending in Nice.

A good day for British riders continued at Tirreno-Adriatico,  another UCI WorldTour event, as Steve Cummings broke clear in the closing kilometres of the 222km stage four from Montalto di Castro to Foligno.

The Dimension Data rider moved away from a breakaway group containing Slovakia’s Peter Sagan, the reigning world champion, inside the final three kilometres to win the stage in 6:04:49.

Italy’s Salvatore Puccio and Cummings' Eritrean team-mate Natnael Berhane finished in the top three after ending 13 seconds down.

The overall race lead stayed with the Czech Republic’s Zdenek Stybar, who remains nine seconds clear of Italy’s Damiano Caruso and Belgium’s Greg Van Avermaet.

Racing is due to resume on Monday (March 14) after organisers announced that the queen stage of the race, scheduled to take place tomorrow, was cancelled due to heavy snow on the route from Foligno to Monte San Vicino.