The Tasmanian has been Chris Froome's wingman, friend and training partner for two years. Now with Froome crashing out early on stage 5, Porte has become the designated team leader at Team Sky.
At the start of the stage in Arras, team manager Dave Brailsford named Porte as team leader in an act of official investiture.
"Richie has become plan A and we've also got plan G (Geraint Thomas)," Brailsford joked, determined that Team Sky will quickly switch focus and still target overall success despite losing Froome.
"We're six days into the race and so if we give up now, we're in the wrong business. It's a long, long race. Now 10 seconds seems a massive gap but at the end it will be about minutes. Anything can happen and we've got to believe."
"I think we've got two great riders in Porte and Geraint Thomas. Richie is relishing the opportunity. He's up for his belief systems are in the right place. I think he's very close to being a GC contender, so one man's loss is another man's opportunity."
"We'd also love to see how far Geraint can get. It's going to be a different challenge but why not try and get a third different winner in three years? Somebody has to win it, so why not one of our guys? You've got to be optimistic."
A nervous day to Reims
Porte finished the stage to Reims safely in the peloton in 44th place, just ahead of Geraint Thomas. They lost teammate and domestique Xabier Zandio in a crash, with the Spaniard forced to abandon due to the fear of a suspected rib fractures.
"It was such a stressful day - horrible actually," Porte said after his first day of leadership.
"The guys were around me all day, and while we lost Xabi Zandio to the crash, the rest of us kept out of trouble and we live to fight another day."
Porte admitted he was disappointed for Froome but had quickly switched his mindset and stepped in to fill Froome's shoes.
"I've got an opportunity to step up and I'm really going to do that now," he said.
"It doesn't change a whole lot for me. I'm in good form. Now I'll ride for myself and not somebody else. We'll see what happens."
Porte revealed that Froome handed him the role of team leader when they met briefly at the hotel after the stage to Arenberg. Froome had some treatment for his injuries, said his goodbyes and then traveled back to his home in Monaco. Porte had to mentally prepare for the rest of the Tour de France.
"I got back to the room and he was there but not much you can say in moments like that. It's sad to see him go out but the race goes on. He wished me all the best for the rest of the race," Porte revealed.
Porte is eighth overall, 1:54 behind Vincenzo Nibali (Astana). He handled the cobbles pretty well on Wednesday, finishing the stage ahead of all the other overall contenders thanks to some excellent work by teammate Thomas.
He will likely rest up during the flat stages before beginning the real fight to take back time on Nibali.
"We'll take it day by day. Get through these next few stages and then see what happens," he said.
"Last year we were lying first and second overall (after stage 8) and we saw what a disaster that was the day after (Porte had a bad day and dropped out of overall contention). But now I'm really looking forward to getting stuck into the mountains.
"Nibali has a good lead and it's up to the rest of us to take the race to him now. It's his race to loose and him and Fuglsang have got a bit of a head start. But I still think the race will be decided in the last week, in the Pyrenees. Alberto Contador is a racer and I think Nibali is too but I don't think Alberto will take this one lightly. I'm sure we'll see fireworks at the weekend. It's going to be an interesting race."