Despite seeing his hopes of a 5-0 whitewash shattered by the rain, with only three overs bowled on Wednesday before the fifth and final match was abandoned, Pietersen said he was satisfied with team's progress.
English captain won his one Test match in charge in August before leading his team to third place in the ICC world one-day rankings with a 4-0 series win over South Africa.
Despite his initial success, Pietersen insisted he will continue to push his players to their limits as they prepare for the Stanford Twenty20 clash in November followed by a gruelling tour of India.
"I would say it has gone better than I could have imagined," said Pietersen.
"Playing a against a quality side like South Africa who have won nine or 10 of their last series means you are an underdog.
"But the way the guys have trained and played has been absolutely exceptional. I can't fault anybody for anything. They have delivered.
"All the guys are just hungry for more success at the moment. A few of our guys in the past may have settled for some sort of comfort zone.
"But I won't settle for a comfort zone, I won't settle for mediocrity. I want people to chuck their talent around and be the best people they can possibly be.
"There is no point living if you can't be the best person you can be. Fair play to the guys, they have been amazing."
The return to form and fitness of all-rounder Andrew Flintoff has been key to England's success and coincided with Pietersen's leadership infancy.
The Lancashire player finished on top of both the batting and bowling series averages and deservedly claimed the man of the series award.
Steve Harmison's decision to come out of international retirement and Matt Prior's improved form behind the stumps were also factors, and Pieterseon paid tribute to all his players' contributions.
He said: "To have 'Fred' performing at those levels is incredible and all of the rest of the team have delivered which has been magnificent.
"At times all I have had to do is make a few judgement calls.
"It's easier to settle in when you're winning but I know of course there are going to be tough times. We're gong to enjoy the good times though.
"The way the guys are training and playing at the moment I don't think much can go wrong at the moment. We know it will do but we'll be ready for it."