Dimitar Berbartov, Zoran Tosic and Nani were also on target for the English champions against the mid-table Chinese Super League side on a humid night in this tourist resort close to China's economic capital Shanghai.
"Really, our forward play and penetration was absolutely first class so for that reason I've got to be absolutely delighted," said United manager Alex Ferguson. "That's an indication that we're starting to come to a pitch in terms of fitness and timing and the tempo of the game."
England striker Owen, who joined United as a free agent earlier this month and has been set a target of 15 goals next season by Ferguson, made his tally four goals in his first four games before being replaced by Wayne Rooney at halftime.
United, who beat FC Seoul in South Korea only 48 hours before taking the pitch, took a while to get going and it was Owen who made the breakthrough with a classic poacher's goal - with more than a hint of offside - after 23 minutes.
"Things are looking good for us with that signing, I'm very, very pleased with it," Ferguson added of Owen. "Of course the acid test is to come (but) ... given his abilities and understanding of play over the last third of the pitch, I think he'll get us goals."
Two goals in two minutes just after the half hour mark put paid to local hopes of an upset with winger Tosic and Berbatov both finding the right angle to beat hapless Hangzhou keeper Jiang Bo.
It was another contribution from the outstanding Berbatov which set up the pick of the goals after 39 minutes, Owen controlling the Bulgarian's flicked pass on his chest before leaping to volley home from the edge of the area.
Nani and two in a row from substitute Giggs reinforced United's superiority early in the second half but Ferguson will not have been impressed with the way substitute Wang Hongyou was allowed room to head the ball past Ben Foster from a corner 13 minutes from the end.
There was still time for Giggs to skip through to complete his hat-trick in the 88th minute and for Hangzhou's Brazilian striker Valdo to make the scoreline marginally more respectable in stoppage time.
"This gives us an idea of the gap between us and the world's strongest teams," said Hangzhou coach Zhou Suian. "It's brought home how far we are behind."
