Larsson now has Jimmy McGrory's all-time scoring record of 50 goals in season 1936-37 and Charlie Nicholas' post-war milestone of 48 in season 1982-83 firmly in his sights.

More importantly, though, Celtic joined Hibernian and Livingston in the semi-finals, but that did not stop the manager taking time out again to praise the contribution of his goal hero.

O'Neill said of the Swedish international: "I thought his goal fantastic, an absolutely brilliant goal.

"No matter how great the ball is in you still have to put it in the back of the net so that was fantastic - he is a truly top-class player."

O'Neill felt his side deserved to beat their capital city opponents and move a step closer to the domestic clean sweep.

The Glasgow giants dominated the first-half, but only had Larsson's 41st-minute header to show for it.

The visitors did make a fight of it after the break, but Celtic hung on to their 1-0 lead.

O'Neill said: "I thought that we deserved to be in front at half-time and I thought we had the lions' share of the game.

"We had a couple of chances after that and some good goalkeeping and defending prevented us from scoring earlier.

"But we got a fantastic goal to get ourselves in front at half-time and I knew Hearts would come out more after half-time and so it proved.

"That did give us more room, but they also gave us more problems and I felt we were a bit tired and leggy, but I have no excuses and I thought we deserved to win it."