Honda's Otmar Szafnauer said Imola represented the first of several significant steps planned by BAR's Japanese engine partner this season.
"The next step is in Canada (on June 13) and there will be two or three more thereafter," he said.
"In the past almost every grand prix we had something, a couple (of horsepower) here or there. This year we've decided to package them in less steps but more significant ones," he added.
"So this was our first one but it was significant from where we started the season. And then the next one is Canada and that will be significant."
Button's pole was Honda's first pole as an engine manufacturer since the late Ayrton Senna's in Canada with McLaren in 1992. The Briton is chasing his third podium in a row on Sunday.
"Senna was the last driver with a Honda pole and that's good in itself," said Szafnauer on a weekend when Formula One remembered the Brazilian triple champion who died in the San Marino Grand Prix of 1994.
"Hopefully, we can win tomorrow, that's really when it counts.
"We did a lot of hard work," he added, saying that reliability had been the main focus in winter testing after a 2003 season marred by engine failures.
"We ran the interim car with the new engine early just to get on top of the reliability and then the other big focus was weight reduction and centre of gravity reduction."
