The Canadian international midfielder fired into an empty net after a goalmouth scramble that saw Benfica goalkeeper Helton Leite deny Kemar Roofe and then James Tavernier head the rebound off the crossbar. Arfield was on hand to smash in the loose ball and send Steven Gerrard’s side ahead and atone for conceding possession in Lisbon that led to Benfica’s late equaliser the last time the sides met.
And the finish drew praise from McCoist, someone who scored 355 for the Ibrox side in his career.
"I'll tell you something the finish itself isn't as easy as it looks,” he told Emma Dodds on BT Sport.
“It comes behind Arfield and it's a great finish. A lot of people will think that's just a simple one but it's not – he moves his body around and hits the ball in such a way to keep it down, it's a great goal.”
Benfica look capable of threatening Rangers and McCoist also praised a recovery tackle from Leon Balogun to help keep the Portuguese out but the pundit was keen to highlight Rangers’ wide areas.
He added: “Look at the strength Rangers have got in the box for the goal – it is Morelos who plays Barisic to put the ball in and then it's the right back having a header off the crossbar – the full backs are so pivotal to the way Rangers play.”