Austria's Matthias Brandle won the fifth stage of the Tour of Britain, a 177.3km (110.3 mile) stage around Devon from Exmouth to Exeter.
The 24-year-old, the lone survivor of a four-man breakaway, held on for a stage win for IAM Cycling in front of Shane Archbold and Maarten Wynants.
Poland's Michal Kwiatkowski finished seventh to retain the lead, with no change in the overall standings.
Meanwhile, Britain's Ben Swift was fifth for Team Sky on Thursday.
His team-mate Sir Bradley Wiggins - who conceded his chances of defending his title were all but over after stage four - was close behind in the peloton and remains sixth overall after finishing 36th.
Brandle, New Zealander Archbold and Belgium's Wynants were in the breakaway along with Germany's Andreas Stauff.
But the Austrian finally prevailed on the final climb up Stoke Hill as they approached Exeter, building an eight-second advantage as Archbold pipped Wynants in a sprint for second place, before the rest of the peloton arrived six seconds later.
"It is the biggest victory of my career so far," he told ITV.
"It was a really hard stage, but I had two guys in the breakaway with me and for me we are all winners. On the last climb, I just tried to go as hard as I could."
Kwiatkowski added: "It was difficult, but I was happy we defended the yellow jersey and I hope we can defend it until London.
"We have to watch out who is in the breakaway, everybody's dangerous so we have to be careful."
|What will happen on stage six?|
|"The spiky profile looks a little scary but there are no big climbs and we should go over them reasonably quickly. They will sting the legs and help string out the peloton but I'm still expecting a bit of a sprint finish, although the terrain might be a bit hard for pure sprinters like Marcel Kittel."Read Ben Swift's guide to all nine stages|
Friday's sixth stage runs 205.6km (127.9 miles) from Bath to Hemel Hempstead.
Stage 5 result:
1. Matthias Brandle (Aut/IAM) 4hrs 32mins 3secs
2. Shane Archbold (NZ/An Post-Chain Reaction) +8secs
3. Maarten Wynants (Bel/Belkin) same time
4. Sonny Colbrelli (Ita/Bardiani) +14secs
5. Ben Swift (GB/Team Sky) same time
6. Rick Zabel (Ger/BMC) same time
7. Michal Kwiatkowski (Pol/Omega Pharma-Quick-Step) same time
8. Kevin Ista (Bel/IAM) same time
9. Nicolas Roche (Irl/Tinkoff-Saxo) same time
10. Jack Bauer (NZ/Garmin-Sharp) same time
Overall classification after stage 5:
1. Michal Kwiatkowski (Pol/Omega Pharma - Quick-Step) 20hrs 21mins 50secs
2. Edoardo Zardini (Ita/Bardiani) +3secs
3. Dylan Teuns (Bel/BMC) +14secs
4. Nicolas Roche (Irl/Tinkoff-Saxo) same time
5. Jon Izaguirre Insausti (Spa/Movistar) +23secs
6. Bradley Wiggins (GB/Team Sky) +27secs
7. David Lopez Garcia (Spa/Team Sky) same time
8. Leopold Konig (Cze/NetApp-Endura) +29secs
9. Sebastian Reichenbach (Swi/IAM) same time
10. Giovanni Visconti (Ita/Movistar) +40secs