Paul Glatzel scored the decisive spot-kick in a 5-3 victory for the young Reds on Thursday night after Bobby Duncan's late long-range strike forced extra-time at City's Academy Stadium to cancel out Nabil Touaizi's first-half opener.
Lewtas saluted the resilience of his side as they secured the club its first triumph in the prestigious youth competition since 2007.
Read on for the manager's post-match reaction...
On his thoughts about the game...
It seems a long time ago since it kicked off! I thought Manchester City were excellent in the first half. I could pick holes in our performance, but I'd be doing them a disservice.