This was a positive day for Chris Froome as he earned back time lost in his stage-one crash, as well as an indication as to just how strong Porte's challenge could be once this race enters mountains, with such a reliable group surrounding the 33-year-old Australian - who himself played such an important role as domestique in Froome's early success.
It was all about the team for Thomas, though, even if he missed out on the yellow jersey by three seconds.
Nairo Quintana (Movistar) lost almost a minute to his chief rivals, while Vincenzo Nibali, Romain Bardet and Ilnur Zakarin also losing decent chunks of time.
"Some days you're on the right side of it, others you lose time but proud of my boys today", the Irishman tweeted.
Belgian team Quick Step came third at seven seconds but because Fernando Gaviria was dropped along the route he failed to reclaim the race leader's yellow jersey, which was instead claimed by BMC's Olympic road race champion Greg van Avermaet.
Overall, Froome is in 18th place, 55 seconds off the pace and still 44 behind 2017 Giro d'Italia victor Dutchman Tom Dumoulin, who with Team Sunweb only lost seven seconds to the Briton today.
Among Froome's main rivals, France's Romain Bardet lost 1:15 on Monday and now trails the Briton by 20 seconds.
BMC was fighting for the stage win just four seconds ahead of British Sky.
"Just going on the feeling, I think we can be pretty happy", Froome said. "We're on track but there's still so much to go through".
"It's a dream. We rode a good time trial and the whole team worked hard", said Van Avermaet.
The 35.5-kilometre Stage 4, which started and finished in Cholet, saw a reshuffling in the overall standings and gave a number of riders who had lost time due to crashes on the opening stage a chance to recoup time. We'll take it day by day.
It was also a very satisfying day for Froome, the Kenyan-born Briton ignoring some booing at the start line and making up some of the valuable time he lost on Saturday's first stage.
"It's amusing because at the end of the day it's just another bike race".
"There's a photo of the team on the podium with Greg in yellow and I think it's one I will cherish for a long time".
Wrong! The Tour de France's stage 3 TTT was an important part of the battle for the yellow jersey.