John Kennedy has called on Celtic to be ruthless against Rangers and end the champions' hopes of an unbeaten Premiership campaign.
Steven Gerrard's side, who wrested the title back from Parkhead to prevent a record-breaking 10 in a row, have won two and drawn one of the three league games against the Hoops this season and also knocked Celtic out of the Scottish Cup.
Interim boss Kennedy believes a series of missed chances, including French striker Odsonne Edouard failing from the spot in the 2-0 cup defeat at Ibrox earlier in the month, have cost Celtic dearly against their city rivals.
Kennedy, who revealed wingers James Forrest and Mikey Johnston are available for the last Old Firm fixture of the season on Sunday at Ibrox after recovering from injury, aims to prevent Rangers finishing the league season undefeated but knows his side have to be sharper in front of goal.
The former Celtic defender said: "We can use it as motivation but we ultimately have to judge ourselves in terms of what we do.
"What we haven't done, in the last two games especially, is be ruthless in the vital moments of the game and take our chances and change the dynamic of the game.
"Especially in the last game, we gave two goals away which put us on the back foot and then with the big moments, when we had chances to get ourselves back in the game, we didn't take them. So we have to be more clinical.
"When you are more clinical it breeds a higher level of confidence and you see more flow in your football.
"These are the challenges we've faced of late. We've not quite been ruthless enough and that changes the whole dynamic.
"The performances are still stable but we have to be better in both boxes, not giving anything away at our end and being ruthless at the top end.
"We want to go out on Sunday and be free in our play but be very organised and know what we're doing and go back to showing what we really are."
Captain Scott Brown will play in his last Old Firm game before joining Aberdeen as player/assistant next season.
Kennedy believes the veteran midfielder will take a bit of replacing at Parkhead and hopes, after a rare fruitless season in terms of trophies, that he leaves the famous fixture "on a high".
He said: "Scott's had a fantastic career here, a very successful one.
"He's been the dominant figure in Scottish football for a number of years now with the levels he's reached, the success he's brought this club and how he's dominated the game over the years.
"It's been a challenging season, one that he probably envisaged would be different for him, but it is what it is and we have to deal with that and make the most of what's left.
"People always talk about replacing Scott Brown. I'm not sure it will be possible but the club will have to deal with life without him and evolve without him.
"Going into the game, it would be good for the team to collectively pull together to send Scott on his way on a high.
"Especially in his last derby game, which he's had great success in, he's been a real iconic figure in these games. It'll be nice for him to have one more before he bows out."
