Jumbo Visma's Primoz Roglic won the three-day Tour de L'Ain on Sunday by climbing to victory on the Grand Colombier mountain as defending champion and his chief rival for the sport's greatest prize Egan Bernal shadowed him all the way.
In this fascinatingly tense war of nerves the race pitched the cream of the rising Dutch outfit Jumbo-Visma against the established elite of the mighty British Ineos team 20 days before the start of this year's Tour de France.
Ineos arrived at the foot of the Colombier with the last three Tour winners.
But Jumbo, here at least, seemed the stronger unit.
This final day of the Tour de L'Ain will also feature on the Tour de France itinerary, stage 15 culminating with the same climb, on the fifth of eight mountain days on the coming edition of the Grande Boucle.
In the final overall standings Vuelta a Espana champion Roglic, a former ski-jumper who came to cycling late, beat Tour de France champion Bernal by 18 seconds with another Colombian Nairo Quintana coming third another 10sec back.
Roglic was delivered to the final kilometre after a powerful performance from three of his team-mates led by 2018 Giro d'Italia winner and former time trial world champion Tom Dumoulin.
Bernal, on his own against Jumbo for 8 kilometres of the ascent, clung on as some of the peloton's top climbers fell by the wayside.
He only lost Roglic over the final 100m of the climb and even then the Colombian never looked flustered as he finished four seconds adrift.
"Our team did a great job again, so I was able to just finish it," said Slovenian Roglic.
"My main ambition for the Tour de France is to put myself on as high a level as possible, that's the main goal."
The pair look set to lead their teams in a mouthwatering clash at the Tour, which starts in Nice on August 29 and which is likely to deliver a definitive generational shift.
Former winners Chris Froome, 35, and Geraint Thomas, 34, were both clearly working for the 23-year-old Bernal during this race.
Thomas took the front of the Ineos train doing the donkey work until the foot of the climb before Froome took the baton until halfway up, grimacing before giving way and training in 12 minutes adrift.
1. Primoz Roglic (SLO/JUM) 4 h 06:24, 2. Egan Bernal (COL/INE) at 04, 3. Nairo Quintana (COL/ARK) 06, 4. Guillaume Martin (FRA/COF) 08, 5. Richie Porte (AUS/TRE) 16.
30. Chris Froome (GBR/INE) 12:16, 47. Geraint Thomas (GBR/INE) 15:52.
1. Primoz Roglic (SLO/JUM) 11 h 21:12, 2. Egan Bernal (COL/INE) at 18, 3. Nairo Quintana (COL/ARK) 28, 4. Steven Kruijswijk (NED/JUM) 56, 5. George Bennett (NZL/JUM) 1:27.
34. Geraint Thomas (GBR/INE) 21:09, 41. Chris Froome (GBR/INE) 26:45