Bruno Fernandes has many different penalty techniques which ensures goalkeepers struggle to save his spot kicks, according to his Manchester United teammate Juan Mata.
Fernandes returned to the starting XI after being rested in the dead rubber against LASK but couldn't help United find a breakthrough in regulation time despite hitting the post.
The deadlock was finally broken just a few minutes into extra-time when Anthony Martial was fouled in the area and Fernandes stepped up to dispatch from 12 yards.
It was United's 21st penalty of the season and the seventh Fernandes has bagged since joining from Sporting Lisbon in the January transfer window.
Mata hailed the Portuguese's work on the training ground which he feels is key to his 100 per cent record from the spot.
"He has different techniques," the Spaniard told MUTV. "It's very difficult for the goalkeeper to know what he's going to do.
"He's scored every penalty and he's practising a lot in training which is good."
Mata's thoughts were echoed by Ole Gunnar Solskjaer after the win.
The United boss told BT Sport: "He knows keepers will wait for him to do the jump.
"He practices both of them (run-ups) and he practices both sides, so he's got them sorted."
"Obviously you never know," Solskjaer added to MUTV. "He's been very composed and very good on pens.
"We were close, couple of decisions against us, it was one of those nights.
"I think we deserved to win but they made it hard for us."
