Valverde has ridden three Tours with Quintana, yet question marks have arisen over his commitment to the Colombian's cause, notably in 2015 when it was suspected he was reluctant to risk a first podium finish for himself by putting more pressure on Chris Froome.
The way the results have gone this season have added another layer of interest. Valverde's first half of the season was simply phenomenal and saw him win classics like Liège-Bastogne-Liège and Flèche-Wallonne, along with three overall stage race titles at Ruta del Sol, Volta a Catalunya, and Vuelta al País Vasco. Quintana, meanwhile, has taken on the notoriously difficult challenge of targeting the Tour de France after the Giro d'Italia just over a month previously, where he seemed to lack his customary zip and finished second to Tom Dumoulin.
"My goal is clear, and I've stated it many times: supporting him, and nothing else. We'll be backing Nairo 100 per cent," Valverde said in a Movistar interview on Saturday, adding that a strong GC position for himself would strengthen Quintana's tactical hand.
"Anything that happens after that on the road is something we can't really plan on. Obviously, I can't lose much time, with the strategical interests of the team. We believe that my position can also be important, tactically. If things go right and we both remain up there in the overall standings, our rivals will have to take precautions against both of us - which might turn out to be good for the team."
After his glittering start to the season, Valverde took a break after Liège to prepare for the second half, which will comprise the Tour de France, Vuelta a España, and World Championships. It wasn't much of a break, though, as he only spent around a week off the bike, before a three-week block of altitude training in the Sierra Nevada.
He returned to action at the Critérium du Dauphiné and rode an impressive time trial, though he did lose ground on the other Tour de France hopefuls on a couple of the mountain stages. Next up is the Spanish national championships road race in Soria on Sunday, followed by the flight to Dusseldoorf next week for the Tour de France Grand Départ.
"I felt good at the Dauphiné. Obviously, not in a condition to target the GC specifically, but I was close to the top guys. Afterwards, I went to Andorra to refresh my mind on some of the Pyrenees climbs and, above all, stay away from the heat we were suffering in southern Spain," he said.
"I'm going to Soria with an aim of riding strong and help the team retain the championship. Of course I'd love to win, but it's not an obsession for me. More than anything, it should be good training for me before the Tour."
Valverde, who finished on the podium at the Giro d'Italia last year before finishing sixth at the Tour, has no worries about Quintana's chances in July, where, assessing the main contenders, he predicts a tight contest.
"I see Nairo very focused on the task. He's training well, he's keeping his mind fresh, and even though it's true he's tackling the Giro-Tour double for the first time, he's always done better at the second Grand Tour in the past when he took on the Tour-Vuelta one. I don't feel like it should be a problem for him," said Valverde.
"I see all the main rivals doing really well - I don't feel like there's one who's clearly stronger to the others, either. At this very moment, it seems like Richie Porte is a bit stronger than the rest, but in a 21-day event, everything can change a thousand times. Froome has shown his quality during the past few years, and with his previous wins in the race we must consider him the strongest favourite, even if it's true that he hasn't shown to be as superior to the rest as he did in the past. Also Alberto Contador, who knows how to approach the race in full condition; Romain Bardet, who finished 2nd last season - I think all favourites are pretty much close, and that should make for an open race, exciting for the fans."