MANCHESTER, England -- Gerard Pique warned former side Manchester United that Barcelona will put the tie to bed if they get the chance in Wednesday's Champions League quarterfinal first leg.

Pique, who spent four years at United as a youngster, returns to Old Trafford this week for the first time since moving back to Barca in 2008.

Barca start the tie as favourites but United come into the clash buoyed by an impressive comeback against Paris Saint-Germain in the last round. Pique says he watched both games against PSG and urged his teammates to take the chances which come their way to avoid suffering the same fate as the French champions.

"I think the PSG tie is a great example," the defender said in a news conference on Tuesday. "I think [at Old Trafford], PSG played better. In the second half they scored and could have scored more.

"But you can't leave United alive. If you can beat them [by] scoring a lot of goals, you have to do it. They have a great history and they showed that in Paris, even with a lot of young lads from the academy. It's a great example for us. We have to be switched on from the first minute until the last."

Pique, 32, spent his formative years at United under Sir Alex Ferguson. The Premier League side's form has suffered since Ferguson's retirement in 2013 but Pique still believes they're England's best club despite currently sitting sixth in the Premier League.

"Since I played here, they have always been one of England's great teams," he added. "Obviously, teams have ups and downs and moments of transition but they're the biggest team in England.

"They consider the Premier League the same as the Champions League here -- if not more important -- and since the Ferguson era they've been the biggest team and will keep on being the biggest team. Things aren't [going as well at the moment] but I hope they change and quickly they get back on top.

"I spent several years here, between 17 and 21, my first as a professional. I played in good games alongside great players and also had some crazy times off the pitch. I left my family and friends to come here and I returned to Barcelona an adult. It's a special game for me."

Barcelona defender Gerard Pique has warned teammates they need to put Manchester United away if given the chance. Jeroen Meuwsen/Soccrates/Getty Images

Pique was briefly teammates with current United coach Ole Gunnar Solskjaer during his time at United and he has fond memories of the Norwegian, who has turned the English side's fortunes around since replacing Jose Mourinho in December.

"It was a great experience to train alongside him," Pique remembered. "He was one of the veterans and he helped me a lot when it came to adapting to the country and the club. I'm happy to see him in charge of Manchester United, he's done a great job, he's won lots of games playing much better. It will be tough and I hope we can win.

"I imagine we will have the ball, but we have to try and control their counters. They have strong, quick players on the break: [Romelu] Lukaku and [Marcus] Rashford. We have to be careful on dead balls, corners, free kicks. We have to avoid giving them away or defend them well."

Barca have won the Champions League four times since 2006 but have fallen at the quarterfinal stage in each of the last three seasons. It's increased their desire to win it this season -- especially after watching rivals Real Madrid win it three times in a row -- but Pique denied the players are under additional pressure to perform.

"Pressure would be if we'd never won it or if this was the only title left for us [to win] this season," he said. "That is not the case. We have done things well this season and that's why we are where we are: [11 points] clear in La Liga, in the Copa del Rey final and in the last eight in Europe.

"Look back and you will see that we have done very well in [all competitions] in recent seasons. So, there's no pressure. There's a lot of excitement."