And James Bolton is certain the Pompey keeper would have become an established Football League regular earlier in his career only for Dean Henderson standing in his way.
Scotland play Euros 2020 qualifiers in Russia tonight before hosting San Marino at Hampden Park on Sunday.
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MacGillivray is competing with Wigan’s David Marshall and Sunderland stopper Jon McLaughlin for a starting spot.
Regardless of whether he makes his debut or not, the 26-year-old has enjoyed a superb spell since arriving at Fratton Park in June 2018.
At previous clubs Walsall and Shrewsbury, he’d been confined to a support-ace role.
Henderson, who's recently been called up to the England squad having impressed on loan at Sheffield United from Manchester United in the Premier League, was ahead in the pecking order at the Shrews.
Bolton played with the pair at New Meadow during the 2017-18 season and felt MacGillivray was unlucky not to have featured more frequently.
But the right-back heaped praise on the affable stopper for becoming a regular at the Blues.
‘I’m buzzing for him, to be honest,’ said Bolton.
‘Craig’s had a similar time to me, being in non-league at Harrogate then having a frustrating time at Walsall.
‘So he’s taken his chance and all is going well for him.
‘There’s a chance he could get a sniff for Scotland. If he does then I’m sure he would do well and take his chance.
‘Fingers crossed he gets that chance.
‘Even at Shrewsbury, you could tell that he was a top, top goalie. But he just had Deano in front of him and there aren’t many better than Deano around.
‘I felt sorry for him at Shrewsbury. I always mention his performance when we won 1-0 at Fratton Park and he played ridiculous.
‘They had a bit of banter between them. Deano is playing in the Premier League now and Craig was a bit unlucky otherwise I’m sure he would have played.
‘But when he did play he always did very well.
‘It wasn’t a case when Deano wasn’t playing that we were going to struggle. You always knew Craig would slip right in and he proved that every time.’
MacGillivray has made 68 appearances for Kenny Jackett’s side and become a fans’ favourite.
Bolton believes the Perthshire-born ace will continue to improve.
He added: ‘Since Craig has come here, he has pushed on massively and I think he’ll continue to do that.
‘Hopefully he can keep kicking on and I am sure he will.’