The Hoops got their opening goal of the afternoon thanks to Jozo Simunovic’s volley on the stroke of half-time.
It was perfect timing for Brendan Rodgers’ men as they’d struggled to open up an organised and frustrating Dees side for the majority of the second half.
And it put a different spin on the second half, with Dundee needing to come out and attack Celtic with the aim of getting back into the game.
Unfortunately for Paul Hartley and his men, they’ve found themselves 2-0 behind just before the hour mark after Armstrong’s header.
It was a nice Celtic move that saw Forrest beat Kevin Holt on the right before clipping a ball to the front post for Armstrong to head into the back of the net:
— CelticGoals (@CelticGoals) March 19, 2017
That’s Armstrong’s 12th goal of the season and comes at the ideal time before he joins up with the Scotland squad for the first time next week.
He’ll be hoping to play a part in the friendly against Canada and proving himself enough to warrant a spot against Slovenia days later in the World Cup qualifier.