Wicketkeeper/opener McCullum was the deserved man of the one-day series in Abu Dhabi, starring with game-high scores in New Zealand's two wins.
His run-a-ball 131 in the second match was McCullum at his best, an innings comprising fluent shot-making, sharp running and, when needed, improvisation to unleash the shackles.
He followed it with 76 off 78 balls in yesterday's low-scoringseries-clincher, giving him 227 runs for the series and defying critics who have grown impatient at McCullum's lack of consistent runs at the top.
The call had grown louder for a shift back to middle-order duties, something that hasn't escaped the 28-year-old.
"I don't usually take notice of external factors but coming over here I felt I was under pressure from all angles," McCullum told NZPA.
"For the first time in a long time I feel I've been able to contribute and play an influential role in games.
"I haven't been as productive as I've wanted over the last year and I've gone back to batting in a similar way that was successful a couple of years ago." The solution? Keeping things simple.
McCullum admitted he had been over-complicating matters at the crease and had appreciated the supportive words of teammates and coaching staff as he sought a return to form, remaining adamant that opener is his best position.
"It was a mental adjustment for me. I was getting a little bit low on confidence after missing out on some big scores over the last little while.
"Obviously the second game was fantastic, it was just a matter of trying to get a start again and get a bit aggressive." McCullum's form ignited the New Zealand team, who suffered a forgettable 138-run loss in the first game.
"Obviously going down in that first game, the boys were pretty hungry to bounce back and I thought we did that incredibly well in both games."
Having passed 50 just twice in his previous 24 innings before leaving for the United Arab Emirates, McCullum was now determined to maintain the rage in New Zealand's two Twenty20 matches on Friday and Saturday (NZT).
"Hopefully this is the catalyst for a strong year and I'll see what I can do in the Twenty20 games," he said.
"We pride ourselves on our shorter version of the game. We've done well in this series and it's another opportunity to perform well away from home." New Zealand have lost both their previous Twenty20 matches against Pakistan, who are world champions in the shortest form of the game.
