A third trip to this part of the world in the past decade was shoehorned into Tottenham's schedule to help boost their global profile, with supporters treated to a couple of goals in the first half and a few more late on at the Hong Kong Stadium, including a consolation for the hard-working hosts.
Spurs soon found their groove, though, opening the scoring thanks to a smart finish from fan favourite Son, just a couple of minutes after he had a goal wrongly ruled out for offside.
Home keeper Wang Zhenpeng was being kept busy by Christian Eriksen, who had a few attempts on target kept out in a fairly routine manner, but there was to be no stopping Janssen's close-range finish once picked out by Ben Davies down the left.
South Korea international Son in particular was enjoying himself during his time on the pitch, cheered throughout by those in attendance, although he felt that he should have had a penalty when tripped in the box after slaloming through a few bodies.
Huang Yang failed to test replacement Spurs keeper Pau Lopez, brought on 30 minutes in for his club debut, from a good shooting position, while up the other end Janssen was denied from close to 30 yards out in the final meaningful act of a first half largely dominated by the Lilywhites.
The visitors made full use of their squad strength by bringing on six fresh pairs of legs for the remaining 45 minutes, with Kane - seven goals in his final two Premier League games - the most notable absentee as he was not used until the closing stages.
Due to the mass changes Spurs took some time to get going again, waiting until close to the hour mark until Son tested Zhenpeng with a rather tame attempt, before the Asian stopper produced a top save to help Janssen's curler onto the crossbar.
Michel Vorm was the third and final Spurs keeper to be turned to, introduced for the final third, and his first involvement was to keep out a shot down low from close range.
Sterling was also among those to be brought on in a stop-start second half, forcing Zhenpeng into a leaping save with a header just moments after being introduced from the bench.
Despite only being brought on with 10 minutes left to play, there was still time for Kane to join the scoring when rolling the ball into an empty net at the end of a swift counter led by Kieran Trippier.
Kitchee, heading into this match on the back of a successful campaign that saw them win the local league and cup, pulled one back courtesy of Lucas's close-range finish following a defensive mix-up.
Sterling regained his side's three-goal advantage late on, however, tucking home when picked out in some space to end things on a high for the Lilywhites after their best league season in 54 years.