Jordi Roura says Barcelona cannot afford a repeat of their last European away performance in Tuesday evening's Champions League quarter-final first leg at Paris Saint-Germain.
Barca were sluggish and blunt when losing 2-0 at AC Milan in February's last-16 first leg, managing just one shot on target all game and regularly getting caught on the break, but turned the tie around when winning the second leg 4-0 at their Camp Nou.
Tito Vilanova's assistant told reporters at Monday evening's pre-game press conference that the blaugrana side had learnt from their mistakes in Milan, and knew they must be at their best to get a result at the Parc des Princes.
"That game showed us what cannot be, what we must avoid," Roura said. "We will not get a good result if we are not at our best. We know this a really difficult game and we cannot allow ourselves to be below 100%. This is football and your opponent can always win, but we know that if we play well we will have a big chance of going through."
Barca's chances of doing that got a boost on Monday when Roura hinted that both key playmaker Xavi Hernandez and left-back Jordi Alba had recovered from hamstring injuries which saw them miss Saturday's 2-2 La Liga draw at Celta Vigo.
"Xavi and Jordi had problems and could not travel to Vigo, but they have been doing specific fitness work," Roura said. "We will see how they feel after today's training session. There is still a while to go to the game."
That would leave just one spot open in Barca's XI, with Cristian Tello, Alexis Sanchez and Cesc Fabregas all options to replace the suspended and injured Pedro Rodriguez in attack.
Roura suggested Tello's goalscoring performance against Celta means the young winger is ahead of the out-of-form Sanchez and Fabregas.
"[Tello] has a chance to play," he said. "He played a great game on Saturday, and brought us very important things - he is a specialist winger. He can run, he is vertical, he scores goals [but] we have some other options."
Barca's apparent return to form in crushing Milan in the second leg has led many in Catalonia to see their team as firm favourites to progress to the semi-finals. However, Roura said Qatari-backed PSG, especially with Zlatan Ibrahimovic freed from suspension, should not be underestimated.
"PSG are one of the best teams in Europe, with a huge budget, with Ibra, [Ezequiel] Lavezzi, [Javier] Pastore," he said. "Whoever thinks this is going to be easy is mistaken. We know [Ibra] very well, he is a great player, special, you need to know how to defend him. They have tall players and are very physical, so dead balls are one of their strengths. Another is playing on the break, but we are used to that. Almost all teams play us like that, waiting for a mistake to attack us."
The game is expected to see Vilanova's return to the Barcelona bench after spending two months directing affairs from New York where he was receiving medical treatment.
"It is important to return to normality after a very difficult situation," Roura said. "The biggest thing is that we are all very happy. Tito is a very much loved person, by the group and everyone at the club."
Alex Song, meanwhile, has told RMC radio Barcelona are in relaxed mood ahead of the match and are doubly determined to do well with coach Vilanova returning to the dugout.
Song, 25, is part of the Barca squad which has jetted into the French capital to face Ancelotti's expensively-assembled side. Although the hosts have ambitions of matching their Catalan visitors in the long term, Song believes Barca have little to fear as they step out onto the pitch in the shadow of the Eiffel Tower.
He said: "We're not worried. Barcelona are a big club. PSG have done some good things recently. It'll be a good game, but we're not worried. We're going into this game with a lot of desire."
One extra source of motivation is the return of Vilanova, and Song said: "We've missed him a lot. We were all a little worried about him. Now he's back. He's going to bring us that little bit extra we were lacking.
"We really want to do well for him. We'll give everything for him. What he gives us on a daily basis makes us better."
Improvement is hard to come by for Lionel Messi, 25, who has struck 50 times in the Champions League in the last five years. The pocket-sized Argentine poses the biggest threat to PSG's 23-game unbeaten streak at home in European competition, and though his talents are well-documented, he still has the ability to impress even his own team-mates.
"It's better to have him with you than play against him. There's not another player like him in the world," Song said. "The Lord came to his crib and gave something to that child to make him the best player in the world. He's proving it now. There's no debate about Messi. It's extraordinary what he does. He's a phenomenal bloke, and he's only 25."