The Australian registered team finished the 21.5km ride against the clock seven seconds ahead of Jumbo-Visma and 22 in front of Sunweb at an average speed of 57.546kph.
“Who would cross the line first isn’t something we talked about before racing," Hep[burn said. "We just rode for winning.
"It was my turn after Alex [Edmondson] and I was first on the line but there was no plan for that. We have a really strong team here at Tirreno-Adriatico and today’s stage suited us as well."
The stage was a calamity for BORA-hansgrohe after the German outfit collided at full speed an errant spectator who crossed the road in front of the seven-rider squad just 3.5km into their run.
"Unfortunately, we had a very bad day, said BORA-hansgrohe Sports Director Enrico Poitschke. "Just 3.5km into the stage, a spectator crashed into the team, taking down two riders and splitting up the squad.
"From then on our guys weren't in the best mood but still gave a fight. The good news is that Rafał Majka is set to continue the race. He doesn't look good after the crash but he will be there.
"Our chances at the GC are probably gone now but we will try to fight for, possibly, a stage win that will keep our spirits high. Still, it was a very bad day for us."
As the last team off the start ramp, Mitchelton-SCOTT had to deal with mixed conditions with the sun having dried some sections of the course, while others remained wet.
Mitchelton-Scott passed the first time check just two seconds down on the fastest time set by Jumbo-Visma before driving on to the finish.
Disaster almost struck heading onto the finish straight when a woman and her dog strayed onto the course but the team sailed past without incident.
EF Education First and Deceuninck-QuickStep also enjoyed some time in the hot seat before Jumbo-Visma came through to take their turn.
The result placed Mitchelton-Scott team leader Adam Yates in a strong position relative to his rivals as he seeks to add the Italian race to his bevy of wins.
"We’ve been trying to win a TTT for a long time, I think I’ve been here four or five years now and every time we try, every year we bring a super strong team and we’ve been close and now we’ve finally got it," he said.
“Tonight we’ll look at the standings and work out where we are, it’s going to be tough, there are no big, super hard mountain stages this year, but we’ll see and just take it stage by stage.”