The pair, dubbed the 'PR show' after notching all the goals in Wednesday's 4-0 German Cup victory over Kaiserslautern, made sure Bayern rebounded in style after suffering their first league defeat last week.
Peruvian Pizarro, who at 34 returned for a second spell at Bayern to play a back-up striking role, has not featured much with top scorer Mario Mandzukic grabbing the starting spot in place of the injured Mario Gomez.
On Wednesday, however, when coach Jupp Heynckes fielded a second string team, Pizarro grabbed his chance with both hands, scoring twice and setting up the other two for Robben, who had returned from a month-long injury break only days earlier.
The Dutch winger's first start since a back injury that had ruled him out for more than four weeks showed he is racing back to his best just when Bayern need him most.
Bayern's 2-1 loss to Bayer Leverkusen last weekend snapped their record eight-win start to the season but their cup performance showed they have learned from their implosion at the same stage last year when they squandered a big lead to end a second straight season with no silverware.
"Despite the many changes in the team, they worked like a unit, with a lot of enthusiasm and discipline," said Bayern coach Jupp Heynckes. "They earned it themselves."
Heynckes will need all the players he can muster againstHamburg, with the northern club in sparkling form after a bad start to the season.
With three wins in their last four league games, Hamburg are giving their fans something to smile about, lifting themselves out of the basement and into seventh place.
"I can't wait for the game. We have three points to lose and we want to win this match," said Hamburg keeper Rene Adler, whose superb saves have fanned speculation of a Germany comeback.
He lost his first choice spot to Bayern's Manuel Neuer after a rib injury shortly before the 2010 World Cup.
"The (Leverkusen) game showed that if we stay compact we can make it hard for them. No team is unbeatable," he said.
Second-placed Schalke, on 20 points, travel to lowly Hoffenheim while champions Borussia Dortmund (fourth place on 15) are looking for their first back-to-back league wins when they host in-form VfB Stuttgart.