Britain’s Adam Yates took the overall lead at the Criterium du Dauphine after finishing sixth on stage four.
The Mitchelton-Scott rider, 26, leads Belgian Dylan Teuns by four seconds following the 26.1km time trial in Roanne, France.
Jumbo-Visma’s Belgian Wout van Aert won the stage in 33 minutes 38 seconds.
Britain’s Chris Froome suffered a “very serious” crash during a practice ride before the stage and has been ruled out of the Tour de France in July.
The eight-day Dauphine ends on Sunday.
Yates began the day 10th in the general classification – 24 seconds down on Bahrain-Merida rider Teuns.
Van Aert, who finished second on stage three, finished 31 seconds ahead of American Tejay van Garderen in second, and 56 clear of Yates.
Van Garderen, riding for EF Education First, and Astana’s Jakob Fuglsang are six and seven seconds behind Yates overall, with only 30 seconds separating the top nine riders.
“It’ll be a massive task to bring the yellow jersey till the end,” said Yates.
“I hope to do it but I’ll take it day by day. It’s going to be tricky. I’m sure the mountain stages will be hard to control.”
Thursday’s fifth stage takes the peloton along a relatively flat 201km route from Boen-sur-Lignon to Voiron.
Stage four results
1. Wout van Aert (Bel/Jumbo-Visma) 33mins 38secs
2. Tejay van Garderen (USA/EF Education First) +31secs
3. Tom Dumoulin (Ned/Sunweb) +47secs
4. Steven Kruijswijk (Ned/Jumbo-Visma) +49secs
5. Emanuel Buchmann (Ger/Bora-Hansgrohe) +51secs
6. Adam Yates (GB/Mitchelton-Scott) +56secs
7. Julian Alaphilippe (Fra/Deceuninck-Quick-Step) +59secs
8. Nils Politt (Ger/Katusha-Alpecin) +1min 5secs
9. Jakob Fuglsang (Sui/Astana) +1min 7secs
10. Remi Cavagna (Fra/Quick-Step Floors) +1min 10secs
General classification
1. Adam Yates (GB/Mitchelton-Scott) 12hrs 27mins 26secs
2. Dylan Teuns (Bel/Bahrain-Merida) +4secs
3. Tejay van Garderen (USA/EF Education First) +6secs
4. Jakob Fuglsang (Den/Astana) +7secs
5. Steven Kruijswijk (Ned/Jumbo-Visma) +24secs
6. Thibaut Pinot (Fra/Groupama – FDJ) +25secs
7. Emanuel Buchmann (Ger/Bora-Hansgrohe) +26secs
8. Alexey Lutsenko (Kaz/Astana) +30secs
9. Wout van Aert (Bel/Jumbo-Visma) same time
10. Nairo Quintana (Col/Movistar) +40secs
