The tie was played at Gibson Park, where Brian Scroggie's lads romped home with 146 runs to spare.
The city side were always up against it when Templepatrick amassed the huge total of 326 for 7 in their 50 overs, after having been in dire trouble in the early stages.
Andrew Patterson, Craig Jennings and Mark Thompson were all back in the pavilion with the scoreboard reading 9 for 3, but then McCombe (149) and skipper Scroggie (56) turned the tables with a stand of 123 for the fourth wicket.
William Stevenson came in following Scroggie's dismissal, and along with McCombe fashioned another 130 runs for the fifth wicket. Young William hit half a dozen sixes in his 58, while McCombe hit almost half his total in boundaries.
In reply Cregagh II were always well behind the required scoring rate, but they batted resolutely for 48 overs before their innings closed on 180.
Opening bowler Peter McDonald did most of the damage with a haul of four wickets, while another young pace bowler, Ian Webber, claimed three victims, with Peter Shepherd capturing a brace.
Commenting, Peter McDonald said: "This was ample revenge for Cregagh's league win a few week's ago in Ballyclare. After that start when we had three wickets down with only nine runs on the board in the fifth over, we were delighted to post such a high score in superb batting conditions.
"John McCombe, Brian Scroggie and William Stevenson all batted brilliantly, and John was unfortunate to fall just one short of one hundred and fifty."
On Saturday afternoon Templepatrick II are scheduled to travel to Saintfield II to fulfil a league fixture.