Scott Sinclair admits Celtic failed to give a true reflection of their capabilities as they were torn apart by Paris St Germain.
Celtic suffered a brutal lesson from Unai Emery's expensively assembled outfit on Tuesday night as they slumped to a 5-0 defeat in their opening Champions League clash.
While many have pointed to the riches available to PSG to justify the merciless nature of the beating dished out by their superstar frontline of Neymar, Kylian Mbappe and Edinson Cavani, wideman Sinclair believes Celtic should have still been able to put up more of a fight.
But the former Swansea and Manchester City player confessed the Hoops' sloppy start left them on the back foot as their French opponents swarmed forward.
"It was really disappointing," said the Englishman. "The first half an hour we started off really poorly as a team.
"In the second, we came back a little bit more lively and created some half chances but the result was so disappointing.
"The way we started was not how we normally start games and it showed.
"The way they came forward forced our attacking players to defend more than we are used to. Me and Patrick Roberts had to get right back and sit in. We tried to counter but sometimes the passes were loose.
"The manager wasn't happy at half-time. He said that wasn't us.
"When we went out in the second half we created a bit more and tidied up a bit with some of the passes - but that's all we could have done."
Celtic have reigned supreme domestically since Brendan Rodgers took over last year but were simply no match for the Parisians.
Neymar, Mbappe and Cavani all netted during a ruthless first-half onslaught, with Mikael Lustig's own goal and a classy diving header from Cavani late on confirming the club's heaviest home defeat in 122 years.
It will not ease the pain being felt by the Celtic support but Sinclair believes there is mitigation for the result in the fact Emery's men look well capable of beating the cream of European football to the Champions League crown.
"They are up there," said Sinclair. "You saw the quality of players they have and the amount of money they spent. They are top-class players.
"I'm sure they will be looking to win the competition. They have got the players to do that and they showed against us their qualities."
Celtic's next Group B appointment sees them travel to Anderlecht in a fortnight's time and defeat to the Belgians would leave their hopes of progression hanging by a thread.
But Sinclair said: "I think every game you play in the Champions League has pressure no matter if you win, lose or draw.
"You just need to keep bouncing on, so we'll put this one to bed and move on."
Rodgers, meanwhile, claimed his side played like under-12s at times in their Parkhead thumping.
The Northern Irishman said: "This is a level where you have to look after the ball and you have to make it work for you. In the first half we didn't do that, we were playing like under-12s at times.
"So like I say, it is confidence, belief. We are missing some decisive players as well who can help us at this level but it is always going to be very tough. That is the reality of it.
"I don't want to be too harsh on the players.
"They (PSG) are the potential champions of this tournament and where we are at, with all due respect, and where those guys are at, it is not just one or two levels, it is three or four levels away beyond.
"We always have to be competitive and we weren't for that first period but the second half was much better and the supporters acknowledged that," he added.