Celtic must believe they belong at the top level of European football if they are to salvage their Champions League campaign, so says Ange Postecoglou.
The Hoops sit bottom of Group F, having taken just one point from their opening three games after losing 3-1 to RB Leipzig on Wednesday.
Celtic came out strong but went in at half-time 1-0 down courtesy of Christopher Nkunku. Despite Jota grabbing an early equaliser in the second half, a double from Andre Silva secured the three points for the Bundesliga side.
Postecoglou thinks Celtic must show more belief in their own ability, citing their mentality will change with more experience.
He told BT Sport: "A lot of it is experience at this level. Guys believing they belong, guys believing they can achieve at this level. It's not easy to translate that to people when they're out there. There's a lesson there for us tonight.
"We know when we're aggressive and play our football, we can cause anyone problems. When we're not, it's going to be very hard for us to be successful.
"For us to get over this hump of being a good side and getting results we have to have a stronger belief and mentality, but that's not easy, it comes with experience.
"If you play for survival that's all you'll ever get, you never get anywhere."
Leipzig's second goal came after Joe Hart made a mistake while trying to play the ball out from the back, and the former England goalkeeper knows his error was a costly one.
"They were pressing with three... I decided to pass to Greg [Taylor] and I missed. It's high-level football, something I love playing, and when you make a mistake you get punished," Hart told BT Sport.
"Sometimes it's going to hurt us but ultimately we proved we could get through the press and gave ourselves some good opportunities to score goals.
"We've got two big games at home in a row. If we play to our potential, we believe that we can win them and then it will look different."
Celtic take on St Johnstone in the Scottish Premiership on October 8, before Leipzig travel to Glasgow for the reverse fixture in Group F three days later.