The veteran striker headed in two first-half goals and proved a menace throughout as the Germans stormed to the biggest win of the tournament to date in their opener at Melbourne Rectangular Stadium.
Having been in spectacular form with six goals at last year's Euros, Popp was a late withdrawal from the championship match due to injury and had to watch from the sidelines as Germany lost 2-1 to England in extra time.
Germany will hope she can go the distance at the World Cup in Australia and New Zealand, as they chase a third title after back-to-back triumphs in 2003 and 2007.
"For me, personally I’m happy that I’ve been healthy this year, that I can be here with my team and support them," she told reporters after the Morocco mauling.
"That to me is incredibly important and gives me strength.
"It was great to start this way... Of course, not everything went optimally, that would be too much to ask of the first match.
"But how we played today, that gives us a lot of confidence for the rest of the tournament."
World number 72 Morocco, the first Arab team to play at the tournament, were hopelessly outgunned by their second-ranked opponents and blew out the score with two own goals in the second half.
But Germany's complete performance was a warning to heavyweight rivals like the United States and England.
Working out how to shut down Popp's work in the box - and the teammates who assist her - will keep coaches up at night.
Popp thumped in her first header in the 11th minute from a Kathrin Hendrich (31) cross, then back-headed a Klara Buehl (22) corner for her second late in the half while spinning and off-balance.
Well-taken goals from Buehl and Lea Schueller in the second half underlined that Germany are no one-woman band but the show seems to go better when Popp is front of stage.
"That our goalscorer is also our captain is great," said Germany coach Martina Voss-Tecklenburg.
"We know how our team operates. Regardless of where Popp is playing, she is captain and a playmaker of the very best."
