PSG – last season’s runners-up – took a commanding lead in the last-16 tie thanks to hat-trick hero Mbappe, who fuelled a stunning 4-1 demolition on Tuesday.
Lionel Messi, whose has been heavily linked with PSG, opened the scoring via a penalty before the French visitors seized control courtesy of Mbappe and Moise Kean.
Ligue 1 champions PSG outclassed and overpowered Barca to put one foot in the Champions League quarter-finals ahead of the return leg on March 10.
Barca head coach Koeman acknowledged PSG’s superiority was clear to see and conceded the embattled LaLiga giants have some way to go in order to compete with Mauricio Pochettino’s men.
“They were superior, they were very efficient, in particular thanks to to Mbappe,” Koeman said.
“The first half was balanced. At 1-0, Ousmane [Dembele] had a good opportunity. In the second part of the match, we had some defence problems.
“They showed that they were superior, with the ball and especially physically.
“They had a more complete team than ours. We have to accept it and keep improving. We know that can happen. This team is ahead of us.”
Barca famously came back from a 4-0 first-leg deficit to send PSG crashing out of the Champions League with a 6-1 second-leg triumph in 2017.
‘La Remontada’ or ‘the comeback’ has become forged in European football legend but Koeman has little hope of a similar turnaround at the Parc des Princes.
“Losing 1-4 is very difficult. There are very few possibilities to come back,” he said.
“We are missing things to be at the best level, especially in the Champions League.”
Barcelona have never progressed in a European knock-out tie after losing their first home game.
It is the first time Barcelona have lost back-to-back home games in the Champions League/European Cup and the first time they have conceded three or more goals in back-to-back home games in European competition.
Meanwhile, Barca have conceded four goals in a knock-out match at home in the Champions League and the second in the European Cup/Champions League after a 4-0 loss against Dinamo Kiev in November 1997.