Xavi Hernandez insisted Barcelona are improving despite another early European exit, this time at the hands of Manchester United in the Europa League on Thursday.

Robert Lewandowski's first-half penalty gave Barca the lead on the night and in the tie, but second-half goals from Brazil duo Fred and Antony saw United advance to the round of 16 via a 4-3 aggregate win.

It continued Barca's poor record in Europe in recent seasons. They have failed to make it out of the Champions League group stages in each of the past two years and were knocked out of the Europa League by Frankfurt at the quarterfinal stage last April.

- Dawson: Barcelona on wrong end of statement win for Man United

"We have been much better than last season," Xavi said. "We came up against Bayern [Munich], Inter and Man Utd this time. These are big, powerful sides, but we were not good enough.

"We have improved, but it wasn't enough. We will try again. We will be self-critical and try to be more competitive and look to improve in Europe."

After an enthralling 2-2 draw at Camp Nou last week, Barca played well in the first half at Old Trafford but lost their way after the break and will not play in any European competition in March for the first time since the 1998-99 season.

Xavi felt Fred's equaliser, which arrived just two minutes after the restart, had a huge effect on the game.

"Their first goal did a lot of damage to us, coming from a 50-50 ball which we lost," the Barca coach said. "We lost the individual duels in the second half. United played with a lot of intensity.

"The first half was good. It was an even tie -- here and at Camp Nou. In spells we were very good, such as in the first half here. The team stepped up, but we lost against a great side in great form."

Despite praising United, Xavi ultimately felt the loss was down to his own side's shortcomings -- and that the absences of the injured Pedri and suspended Gavi made a big difference.

"It was more down to us, we lacked patience in the second half," he added. "If Pedri and Gavi are playing, I think the second half could have been different.

"It's not looking for excuses, but the pause they play with, how they turn. It allows you to play in the opponent's half.

"Sergi Roberto was good. [Franck] Kessie very good, like Frenkie [de Jong]. But for the way we play, they would have been really good for us here. That said, the first half was excellent and it's a shame we are out."

Domestically, things are going much better for Barca. They have already won the Spanish Supercopa, are eight points clear at the top of LaLiga and have a two-legged Copa del Rey semifinal coming up against Real Madrid.

"The only positive is that on Sunday we have a game, so we focus on Almeria," Xavi said. "Then [we focus] on the semifinal of the Copa next Thursday. Those two competitions remain and they are very important for the club."