Things have changed since Barcelona's historic comeback against Paris Saint-Germain in the last round of the Champions League.

When Barcelona routed PSG 6-1 to reverse a 4-0 first-leg deficit in the last 16, its confidence was high from winning four games in a row and outscoring opponents 15-3 before that second leg.

This time, it has to overcome a 3-0 first-leg loss against Juventus in the quarterfinals on Wednesday. But without the boost of a winning streak. Barcelona has lost three of its seven games since that spectacular victory over PSG at the Camp Nou.

From leading the Spanish league by one point before beating PSG, Barcelona has dropped to second, three points behind, and hasn't been playing well.

It lost at Malaga 2-0 before the defeat to Juventus in Turin, and had to claw its way past Real Sociedad 3-2 at the weekend.

"There's only one option: Attack, attack, attack," Barcelona coach Luis Enrique said.

"This is similar to the PSG match but in theory we need to score fewer goals. Juve will have their chances, too, so our objective is to score five times."

He said fans shouldn't leave in the 80th minute because they could miss another historic comeback. Barcelona scored three goals after the 87th minute in the win over PSG.

"We are the same team and we can repeat that," said Neymar, who led Barcelona with two goals and two assists in the victory over PSG last month. "We have to give everything we have. We believe that we can come back again."

A contribution from Lionel Messi would be helpful, too. He's scored a pair in three of his last five games. He netted twice each against Valencia, Sevilla, and Real Sociedad, but failed to score in the losses to Malaga and Juventus.

Juventus pays no mind to Messi's middling form.

"These guys are like sharks," Juventus defender Giorgio Chiellini said of Messi and Co. "If you show a sign of nerves, they smell the blood and finish you off.

"Instead, you have to push them back as far as you can, double up when they are in possession, and shut down the lines between defense and midfield."

If Messi scores twice against Juventus, he will reach his 500th goal in official matches with Barcelona. He would be the first player to reach that mark with the club.

Messi has played 575 games since making his debut for Barcelona in 2004.

Barcelona is trying to return to the Champions League semifinals for the first time since beating Juventus in the 2015 final to win its fifth title.

"We must take charge of the game," Barcelona midfielder Andres Iniesta said. "That's our mentality. We need a perfect game, tactically, mentally, and physically."

Juventus, looking for its third Champions League title, is coming off three straight victories. It has lost only one of its last 19 matches, winning 16 of them, and leads Serie A.

It remains unclear if Juventus will be able to count on forward Paulo Dybala, who scored twice in the first leg. Dybalal hurt his ankle at the weekend in the 2-0 win at Pescara.

Barcelona will have back midfielder Sergio Busquets after he missed the first leg because of a suspension.

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