Brutal Richard Foster insists Celtic will score as many as they want against Rangers if they repeat their Alashkert showing.
The Armenian minnows held the Covid-hit Scottish champions to a goalless draw in the Europa League playoff.
Alfredo Morelos first leg goal proved to be the difference between the sides as Steven Gerrard's side booked their place in the group stage.
However, unimpressed Foster delivered a brutal verdict on his former side as they prepare to host Ange Postecoglou's side at Ibrox on Sunday.
When asked about Rangers needing to improve their performance levels on BBC Sportscene following the Alashkert draw Foster said: "Yes, massively.
"If they play like that on Sunday Celtic will score as many as they want I think.
"The heat probably played a factor, they never got to play their normal game, where they kind of hunt in packs and press teams.
"Then that just kind of got it's way though their whole performance and they just never got going.
"Saying that, Morelos should still score three goals. The last one he has probably got to header it.
"It's not a convincing performance, but the main thing is they are through to the next round.
He added: "I think on recent performances, I think Celtic are the favourites."
