Paul Sheerin gave Calvin Ramsay pass marks after watching the Aberdeen teenager impress on his first top-team examination.

The 17-year-old full-back was handed his first start for the Dons as they scraped past Dumbarton 1-0 to reach the last 16 of the Scottish Cup.

There was concern midway through the second half when the youngster went down injured.

However, Reds caretaker boss Sheerin is hopeful Ramsay was merely suffering from cramp as he insisted the Pittodrie academy graduate should be proud of the way he performed against the Sons on his full debut.

"He's OK," said the relieved Dons coach. "Calvin hasn't played a lot of football. He's been injured. He's just come back into things.

"I'm presuming it's just cramp initially and I'm hopeful it's nothing more serious.

"He grew into the game. He loves going forward but maybe he needs to tighten up defensively at times – but all young players do as they learn the game.

"He's a confident lad and loves getting on the ball and putting crosses into the box.

"I thought he did that really well, first half especially, plenty crosses into the box. For a full debut it was a decent one."

Callum Hendry climbed off the bench to fire just the second Dons' goal in 11 games as the mis-firing Premiership outfit dodged a major upset against Jim Duffy's League One part-timers.

The on-loan Saints frontman was also the man that scored their only other goal during that miserable run and Sheerin admitted he always had Hendry in mind for a super-sub role after opting to start with Flo Kamberi.

"Callum was excellent," said Sheerin after watching the 23-year-old pounce with seven minutes left to spare Aberdeen's blushes.

"The way we wanted to step up meant it was just a different type of striker that we opted for at the start.

"But I always had it in my mind that I'd need to get him on at some stage because of the way he's trained this week.

"I'm really pleased to see him get his goal. He showed how sharp he is in and around the area with his quick feet then doing the keeper with his eyes as he stuck it in the corner."

The Dons passed up a string of chances before Hendry's strike clinched victory.

Sons keeper Sam Ramsbottom was in inspired form on his 25th birthday but there was no icing on the cake for Dumbarton as they bowed out.

Speaking to the club's website, Ramsbottom said: "It's not every day you get the chance to create a shock result on your birthday.

"We couldn't do that today, but it's been an alright day. Hopefully we can carry the positive aspects of our performance today into the league and put results on the board.

"We tried to hang on in there but they got the better of us in the end."