Bell (167) ended his run of 19 Test innings without a century, sharing stands of 142 with Gary Ballance (156) and then 106 with Buttler (85) to ensure England piled up 569 for seven declared. Once James Anderson took the wicket of Shikhar Dhawan in India's 25 for one at stumps on day two of this third Investec Test, England could begin to hope for a series-levelling victory.
For Bell, there were several reasons for satisfaction on an emotional day - he looked skywards, on reaching his hundred, in memory of grandfather William who died earlier this month.
The help he was able to give Buttler, almost caught at slip on nought during a nervy start to his international career, was especially rewarding, too, for one of England's most established senior players.
"He was outstanding," said Bell of the younger man. "I think he nicked one that didn't quite carry ... and it looked like he was thinking a little bit too much. We spoke after that about playing the way he plays: the natural instinct he has. As soon as that happened, he got off with a nice back-foot punch for three and, from then on, he looked like the Jos Buttler that we see play county cricket or ODIs."
Buttler was dropped again on 23 at slip, and should have been stumped on 59 but, in an innings designed to fit the match situation, his nine 4s and three 6s off 83 balls were an instant reminder of the limited-overs deeds which have got him into the Test reckoning.
"That's the kind of player he is, and has to be: see the ball, and hit the ball," added Bell. "If we get platforms for him to come in, he's going to come in and move that scoreboard on and get us into match-winning positions; no doubt."
Bell acknowledges Buttler will not always have circumstances made to measure, but is confident he has all the necessary talent. "We know how much potential he has. It's huge, isn't it? That hundred he got against Sri Lanka at Lord's [earlier this summer] was as good a hundred as you'll ever see in one-day cricket.
"Obviously, there will be different tests along the way in Test cricket. If he comes in and we're in trouble, then he's going to have to find a different way. But if we get a platform like that, he's as exciting a young player as you can have coming in at that point.
"He is a laid-back guy, and I think that's good. We want to keep that. He needs to go out and play aggressively, that's when he's at his best ... with no doubts about anything. We want an aggressive Jos Buttler."
Bell's own return to form was much-needed by England. "It's been really frustrating, for all of us," he said. "I've been finding strange ways to get out, getting starts, and not going on, which is frustrating. I hope we're in a good position now to push this game forward. As a batting unit, we want to get back to those kind of habits - 560 declared, rather than the bowlers getting us to 450."