Romelu Lukaku admits Manchester United will find it more difficult to stage a successful Champions League comeback against Barcelona than the one they managed against Paris Saint-Germain.
United booked their place in the Champions League quarter-finals with a remarkable 3-1 victory over PSG last month and were rewarded with a tricky tie against Barcelona.
But Ole Gunnar Solskjaers side face another uphill battle after Barca left Old Trafford on Wednesday evening with a 1-0 win following Luke Shaws own goal in the first half.
United failed to register a shot on target during their clash against the Spanish champions, and Lukaku has stressed that his side need to show significant improvement in the return leg at Camp Nou next week.
