The Saracens centre took the international stage by storm to help Wayne Pivac’s men get their Guinness Six Nations campaign off to a flying start with a bonus-point triumph over Italy.
Tompkins revealed he pointed to the sky during a passionate celebration of his maiden Test score to thank his Wrexham-born gran Enid for making his rugby dreams a reality.
“The celebration was for my gran – she’s the reason I’m here,” he said.
“I had no control over it, I went blank. That celebration was emotion and probably a bit of anxiety and relief all together. It was one of those moments I’ll never forget.
“I just wanted to get on, contribute, and do well. You don’t expect stuff like that to happen. It was unbelievable.
“All my family were at the game. My grandmother was on my mum’s side so mum was really happy.”
Tompkins’ first appearance in a Wales match day squad saw him start on the bench against Italy.
He was thrust into action in the first half as a temporary replacement for Johnny McNicholl who left the field for a head injury assessment.
In that time Tompkins won a crucial turnover and delivered an inch-perfect pass to Leigh Halfpenny in the build-up to Josh Adams’ opening try.
After the break Tompkins came on permanently for Hadleigh Parkes and continued to impress.
He scored a fine second-half try and celebrated in style to cap an afternoon to remember.
Tompkins believes his new group of international colleagues can kick-on to retain their Six Nations crown after sweeping Italy aside.
Adams ended with a treble against the Azzurri while Tompkins and George North completed the scoring in a stunning 42-0 win.
Next up for Wales and Tompkins is a trip to Dublin to face Ireland on Saturday.
“We’re all hungry,” he added. “It’s a new challenge with the new coaches. We’re all heading in the right direction.
“The attitude is brilliant. With he players we’ve got, we’ve good leaders who are going to keep us on the right track. So I think if we stay hungry, keep improving, and keep wanting to improve, we’ll be alright.
“I’m going to take any opportunity I can and then it’s up to Wayne. Hadleigh is such a good player so I’m just going to help no matter what role I’m playing and contribute to hep this team get where it needs to be.
“I calmed down after having those first 10 minutes on the pitch. I sat on the bench and said ‘OK, that’s the level. You’re OK, you can do it’. It was a blessing in disguise.”