The match-winning goal came when Emiliano Tade fashioned room for a shot but then fired across the face of goal. His effort was straying past the outside of the back post until Lewis slid in at full stretch to guide the ball past Jianqiao Gou in the Kitchee goal.
It was, at times, a combative affair and required the Navy Blues to soak up large periods of pressure from the home side - determined to win the trophy in front of their own fans - before Auckland would patiently work their way forward again.
Lewis almost grabbed a second just before halftime when put through on goal but his lob over the goalkeeper just bounced past the outside of the post.
"There were many things to be proud about," said Tribulietx. "I think we dominated the first 60 minutes of the game especially in the first half when we were very good with the ball.
"We went one nil up and Clayton Lewis had a very good chance in front of the keeper. It could've been two nil at halftime."
In the second half, Kitchee pushed forward in waves but City's defence looked comfortable enough to limit the home side to very few clear chances although their were signs of fatigue starting to show.
"Things can change at this level when you start to tire. They brought on six subs on who were of the same calibre as the players they replaced and as we tired we got our pressure a little late.
"Out wide they were pushing their wingbacks on to make it a five up front. It was difficult to defend but they didn't really have any clear chances."
In the day's earlier game, Muangthong United beat FC Seoul 1-0 in a playoff for third place.
The Navy Blues won't have long to celebrate another giant killing excursion as they return home to resume domestic duties, with a Stirling Sports Premiership match against Hawke's Bay United in Napier on Sunday kicking off a run of seven national league fixtures in 28 days.
