Rangers' woes worsened after the break, with Ross McCrorie dismissed for pulling back Moussa Dembele, who converted the resulting penalty.
Brendan Rodgers's side will complete an unprecedented double treble if they can overcome Motherwell when they return to Hampden on Saturday, May 19.
"We have had a really good training week and we enter into it to win".
"In the second half, we gave them the penalty and sending off which makes their job far, far easier". Every game is different and I have enjoyed every single one.
Celtic won a domestic treble last season without losing a match and Rodgers, who has won six out of six games at Hampden since taking over in 2016 and is unbeaten in nine Old Firm games, is well aware of what could be achieved, though is looking no further than Sunday.
Asked what he thought the defeat meant for his own position, he said: "I'm not going to talk about my role". We have to put on a performance worthy of their support.
Rangers just want a victory to get one over their rivals, god knows they haven't had a whole lot to brag about in recent years. We were just passive.
'But we want to finish the season well and be back here and look forward to the final with good confidence.
"There was emotion, anger, disappointment in our dressing room - all the things you would expect after a game like that". I don't think we got close enough to them.
There could be difficulties in agreeing a new deal though, as Australian football website The World Game reported in February that the player had turned down a new deal with the Hoops, although this was denied by Rodgers, as reported by Fox Sports Australia. "It is about making sure they turn that into positives and energy to power us through to the end of the season, rather than allowing it to be disruptive".
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