As nicknames go, it is one of football’s most unusual. Luis de Barros Lopes’ father had it before him.

So, the kid growing up kicking a football in the parks of Lisbon also took on the sobriquet of Duk and, following his two goals against St  Johnstone at the weekend to lift the gloom that had been hanging over the heads of him and his Aberdeen team-mates, who had gone six games without a win, he aims to turn it on in the Viaplay Cup semi-final against Rangers next Sunday.

The 22-year-old attacker, powerful and fast, gave the visitors a torrid time throughout and now has his sights set on making an impact in what he reckons is the most important game of his career as he considers putting in a call to his former Benfica B team-mate Jota, now starring with Celtic, to discuss how to unpick the Ibrox defence.

He said: “Yes, we played together in the under-19s and in the youth league. He is a good player and I keep in touch with him.

“I spoke to him before I moved to Aberdeen in the summer. I asked him about the league and about Scotland. He told me it was too cold!”

Duk certainly increased the temperature for the home fans on Saturday and with nine Premiership goals to his name in 21 appearances, he is now beginning to look a bit of a bargain at the £400,000 paid for his transfer.

“I have a lot to develop,” he conceded. “I am a player who likes to work hard.  I don’t promise anything but I will keep trying and working hard.

“For a striker, it is always good to score two goals. I am so happy.

“We have fantastic fans and I love them so much.

“When I am in the street, people come up to me and ask me how I am.

“This is great, but the big difference from being in Lisbon has been the weather. It is so cold here, but it has been a good time. I have always been a player who likes to fight with the big centre-backs. It is one of my strengths.”

Rangers will have taken note of that strength, in addition to his electrifying pace and the directness of his play.

They will remember, too, that he scored against them as the Govan side recorded a 3-2 win at Pittodrie last month.

Now, he looks forward to appearing on the Hampden stage in six days from now before a packed stadium.

“All the players like to play in big stadiums with a lot of fans,” he said. “I am excited to go there and do a good job.

“Rangers are a big club with good players. We were unlucky with the result last month but we played well.

“We will be going into this game to win. We have the quality to go there and win.”

For St Johnstone’s Tony Gallacher it was something of a red-letter day to face Aberdeen, his first start since breaking his leg in the win over Livingston in April last year.

But he had little else to celebrate at Pittodrie.

He said: “I’m just glad the manager’s got the confidence to put me in and obviously give me the full game as well.

“So hopefully I can now get a good run of games and build that confidence and get familiar with it all again.

“When you are watching on it’s tough, you just want to be involved with your team-mates.

“Just going out, with the fans in the background, it’s what you want to do every weekend.”

The defender referenced Aberdeen’s first strike, in the 74th minute, which started with a long kick-out from goalkeeper Kelle Roos.

He said: “When you give that goal away, though, it’s obviously hard to come back at a ground like this.

“So we made it hard for ourselves."