It took him 13 appearances across five years since his senior debut to score for his country but Griffiths never harboured any doubts he would ultimately prove he could thrive at that level.
“I know myself that I’m good enough,” he reflects. “When you speak to my team-mates, they always say I’m good enough. I’ve never had a manager say I wasn’t good enough.”
Maximising that ability, recognised by a series of bosses at both Celtic and Scotland, has been a different matter. Now 27, Griffiths is in the peak years of his career and believes he has found the improvements demanded of him for the lone striker role deployed by both his club and country.
“I am always on the training pitch when I’m fit, trying to work on my weaknesses and trying to get better,” he added. “You’ve seen over the last 18 months or so, working with Brendan Rodgers at Celtic, that my game has come on leaps and bounds.
“It’s not about proving people wrong for me – it’s about folk just opening their eyes and seeing what they’ve got in front of them. For the first six months under Ronny Deila at Celtic, he wasn’t happy with the way things were going but, when he gave me a chance, I proved myself.
“It was exactly the same the second season when he brought Nadir Ciftci in and I had to do it again.
“Then people said ‘you’ll have to prove yourself under Brendan Rodgers’ but people forget that I started last season well and if I hadn’t got injured, Moussa Dembele would have been kept out of the team for longer.
“But I couldn’t fault Moussa’s contribution after I got injured and it was harder for me to get in. I’ve started this season well and hopefully that continues without any injuries.
“Whenever I had my chance with Scotland, I just tried to do my bit for the team. I thought I played well against Slovenia at home in March, albeit I missed one of the worst chances I have ever missed in my life.
“But apart from that, I thought my link-up play was good. I tried to bring others into play.
“At this level you need that. I spoke to Brendan Rodgers and he said my game has gone to a different level since I came back in the summer. That can only be a positive thing going forward.
“With Scotland, I’ve never thought I wasn’t the manager’s type of player. I would think that if I got left out a number of squads in succession, but the fact I am always in squads and I always get an opportunity to play means that I must be doing something right.
“You have got train well all week, be doing things at club level and force your way into the manager’s plans. He has got to pick 11 boys he thinks can contribute to the game. If not, there are guys on the bench who can come on. Guys like Steven Fletcher and Chris Martin had done themselves justice before me by starting games and scoring goals. That is what I had to start doing.”
Having broken his international duck against England, Griffiths will look to build his scoring momentum in the crucial World Cup qualifiers against Lithuania in Vilnius tomorrow and Malta at Hampden next Monday.
“It doesn’t make a difference to me who the opposition is – if a chance falls to me within 20, 25 yards I’m having a shot at goal,” he said. “If it goes in, it goes in. If not, I’ll wait for another chance. You might not get many chances so you try to make the first one count. But, first and foremost, it’s about the team you play for, whether it’s Celtic or Scotland, and it’s about getting the three points or getting through to the next round.
“After my miss against Slovenia, when I hit the bar, I thought ‘is this ever going to happen?’.
“Then I hit the post two minutes later and thought ‘well, it’s definitely not meant to be.’ And then the England game obviously speaks for itself. You could see the joy on my face when I scored the first and the second one was even better. Hopefully, I can add to my tally on Friday night.”
Griffiths admits he has almost worn out his Sky Plus recorder at home with his repeat viewings of his free-kicks against England. No-one in the Tartan Army will begrudge him the self indulgence.
“I couldn’t tell you how many times I’ve watched them,” he laughs. “Whenever I’m in a bad mood, coming home from training or after a game or whatever, I’ll put that on and it’ll make me smile.
“It means a lot to me but it wasn’t just that, it was the magnitude of the game. To score two goals against anybody for your country would be good but to do it against the Auld Enemy was magic. It’s something I will never forget.”