Pietersen, who returned to the squad at the beginning of this tour, struck a fluent century on day one against Haryana and Bell believes that it is important that the 32-year-old has found his form ahead of next week's first Test in Mumbai.
"Everything's gone really well for us as a group, and for Kevin," revealed the Warwickshire batsman. "He's very much a guy who just likes to get bat on ball, and I think he'll be very happy going into the first Test match with that kind of innings under his belt.
"I'm sure he'll be a lot happier today, having scored a hundred. But he'll be a lot happier if he scores one in the next Test.
"We know if he gets in he can turn a Test match. So we want him in the best nick we can. The pressure is a lot more on the bowler when he does things like that."
Bell will miss the second Test in Kolkata to attend the birth of his child.