Tom George's eight-year-old won the Melling Chase at Aintree following the shock fall of the Willie Mullins-trained superstar Vautour.
The pair did battle once more in this two-mile Grade One and God's Own beat Vautour by two lengths.
Simonsig ran a fantastic race to finish in third.
Vautour was unsurprisingly a warm order to get back on the winning trail as the 4-9 favourite.
With Special Tiara adopting his customary front-running role, Vautour and God's Own sat in his slipstream.
They were just ahead of the talented but fragile Simonsig, on his first start since November and his first outing over fences in over three years.
The leading quartet pulled clear from the home turn and there was little to choose between all four jumping the second-last fence.
God's Own and Simonsig looked set to fight it out jumping the final obstacle and it was Paddy Brennan's mount who found most to win, while Vautour stayed on to grab the runner-up spot.
"For the first mile I had no control and I just let him go, but to be fair he came back then and I filled him up. He was awesome," said Brennan.
"It's great to ride a big one on my home turf. This is where I'm from and it's a proud day."
Analysis
Cornelius Lysaght, BBC horse racing correspondent:
"An emphatic success for God's Own who beat Vautour fair and square here. Despite his recent Aintree win and this second Grade One victory at Punchestown, the winner is one of those - and it happens in all sports - that is clearly good, but you feel has never entirely got the credit he deserves.
"Maybe it's because he's never done it at Cheltenham, but this was terrific. Vautour didn't jump like he can, and requires further than two miles, while Simonsig, racing for only the second time in over three years, ran a stormer."
God's Own followed up his recent success at Aintree with a 9-1 victory over the odds on favourite Vautour in the Champion Chase at Punchestown.