Keane, on-loan from Tottenham, struck a superb hat-trick in Saturday's victory over Kilmarnock.
Keane has now scored eight in nine games since his January transfer window switch but he believes yesterday's haul was the most important yet.
The Scottish Cup remains Celtic's only realistic hope of a trophy this season and the Republic of Ireland international is desperate to make sure he doesn't leave Scotland empty handed.
He said: "It was important.
"A club like Celtic need to be involved in these competitions and get to finals. It would have been disappointing for everyone if we had lost. We can now look forward to the next round.
"It would be brilliant to take a Scottish Cup winner's medal down the road. I'm only here a short time and to win something would be fantastic.
"We need to finish the season on a high note.
"We have picked up in the last few games, kept a few clean sheets and who knows what we can achieve if we continue that to the end of the season."