"Everyone in Colombia is watching the Tour de France and I feel like my nation's representative", said Gaviria.
Sagan moved to the front of the small bunch hunting for position, reaching a speed of 57.6 kph on the final 500 metres on his way to the finish line. With Colbrelli about to catch him, Sagan thrust forward to ensure victory.
Patrick Bevin is a Tour de France stage victor. It was climbing a little bit in a headwind and already the last five kilometres were up and down.
"It's a ideal day, " Sagan said. "Everyone is working well together and we have a strong team and Richie can be up there".
"We have to respect that he's allowed to race, and within a safe environment, and he's had all kinds of abuse at the moment and no athlete should have to go ride under that and have their safety questioned at the sport's biggest event".
Bahrain-Merida is also focused on other riders, preferring Wout van Aert - widely considered the biggest future talent in Belgian cycling, to Van Avermaet, who, while being Olympic champion and a Paris-Roubaix victor, is already 33 and perhaps past his very peak.
Froome is 1:07 behind Sagan's leading time as he pursues a fifth Tour title.
New Zealand cyclist Patrick Bevin helps BMC Racing to team time trial victory at Tour de France. The 22.1-mile loop starts and finishes in Cholet.
Among Froome's main rivals, France's Romain Bardet lost 1:15 on Monday and now trails the Briton by 20 seconds.
The team time-trial might not be the opening week Tour staple it once was, but after the bruising high-octane action of the opening weekend, it represented a major chance for the GC contenders to make some major time gains - or claw back lost time - over their rivals.
Team Sky, another unusual early starter, were booed by roadside spectators throughout their effort but posted nearly identical times through the first two time checks - as did BMC Racing, who also found themselves in an unfamiliar early start time.
Sylvain Chavanel (Direct Energie), Dion Smith (Wanty-Groupe Gobert), and Michael Gogl (Trek-Segafredo) set off on a breakaway after the start, but the 39-year-old Chavanel soon shed the other two in his record 18th Tour participation.
"I don't think it is a bad thing to have the yellow jersey for a team looking for a sponsor", said Porte, who crashed out of last year's Tour and lost time in Stage 1 of this edition.
Astana climber Luis Leon Sanchez later called it quits after he fell and bloodied his left arm.