The Australian was unable to follow when Daniel Martin (Etixx QuickStep) and Froome surged clear towards the top of the final ascent. After a frantic and pulsating day of racing, the BMC Racing rider was forced to limit his losses and despite the slight crack, he did just enough to hang onto his second place with Romain Bardet (AG2R La Mondiale) tied on the same time.
"In the end, I was missing a bit but it was just such a hard day and I haven't done a lot of racing, I certainly paid for that today," Porte said at the finish.
The stage was won by Thibaut Pinot (FDJ) and punctuated by Alberto Contador (Tinkoff) attempting to split the race on the early climbs and then on the long ascent of the Col de la Madeleine.
"For sure all those guys attacking so far out – it was just a hectic day – and that's what you're always going to get with those short sharp stages. Today the guys were fantastic around me and I think tomorrow we've just got to finish it off."
Porte praised former race leader Alberto Contador who, as expected, sent riders up the road and then attempted to go clear on the Madeleine himself. His efforts proved in vain and he was unable to isolate Froome but his aggressive approach certainly tested his rivals.
"Contador was incredible today. To attack at the bottom of the Hors Cat, he's obviously recovered from yesterday but I think they're all going to pay for it tomorrow because it's another hard stage," Porte said.
Porte's long-term goals remain success at the Tour de France but he aims for a strong Dauphine performance for a number of reasons. A podium here would give him confidence, and suggest that he is moving in the right direction. It could also influence BMC Racing's leadership pecking order come July. The Australian admitted that he suffered today and was relieved to chalk off another difficult day in the mountains.
"It was more the legs. It was no surprise that they're always going to go for it in the finish and I was struggling a bit. It was such a hard day. There was never an easy moment and it's good to get that one done."
The former Sky rider was asked if he could see Froome slipping up on the final stage of the race. Should the seventh stage go to form then the British rider should seal his third Dauphine crown and Porte pointed to the depth at Team Sky as one of the reasons for Froome's successes and consistency.
"He can still have a bad day too, but as a unit they were incredible today, people were throwing everything at them and I think those guys are going to pay for it tomorrow because today was a hard day."