Micky Mellon claimed job done after Dundee United struggled past Forfar and into the quarter-finals of the Scottish Cup.
The League One's bottom side gave as good as they got in a goalless first half at Station Park although United attacker Nicky Clark struck the woodwork with a free-kick.
Forfar kept battling after the break but midfielder Peter Pawlett's low drive in the 55th minute ultimately gave the visitors a 1-0 win and set up an away tie against Aberdeen or Livingston.
Mellon told BBC Scotland: "Glad to get through, delighted to get through.
"We came to do a professional job to make sure we are into the quarter-finals and we done that.
"It was quite a sticky 4G pitch, we had to keep plugging away and we knew eventually that bit of quality would tell and we would get that goal.
"That's all it's about, getting into the next round.
"Of course you always want to do more and score more goals but the important thing is we are in the next round."
Pawlett played down his crucial goal, saying: "It was a bit of a sclaff to be honest and it nestled into the bottom corner but they all count.
"It was a massive game for them but it was a big game for us as well.
"We just needed to take care of the ball at times, the pitch doesn't help but we are through and that is the most important thing. It is massive.
"We have an opportunity, we are in the quarter-finals and we want to go as far as we can.
"Livingston or Aberdeen will be tough but we look forward to it."
Forfar's caretaker player-manager Gary Irvine said: "I can't fault the players.
"We had our chances and it is fine lines, we just have to be more clinical when those chances come, unfortunately Dundee United took theirs."