Former Valencia manager Pako Ayestaran has explained in detail how Chelsea can defeat Barcelona at the Nou Camp on Wednesday night.

Lionel Messi's equaliser in the first leg of their Champions League last-16 tie means Chelsea must equal the same 1-1 scoreline to force extra-time, or beat the Catalan giants outright, if they want to advance.

Ayestaran achieved the latter in April 2016 which almost cost Barca the La Liga title, and the ex-Liverpool assistant has revealed how Chelsea can repeat the same feat.

His first piece of advice for Conte was that he makes sure their isn't any space afforded between the lines.

"When you come to Barcelona, you have to accept that you are not going to have much of the ball," Ayestaran told Sky Sports.

"You also have to take a decision who you want to allow on the ball - which you are going to allow more time to, and which you are going to press as soon as they get the ball.

"Chelsea did this quite well in the first leg. They allowed time to the centre-backs, to the two midfielders, Ivan Rakitic and Sergio Busquets, knowing they are not the danger. The danger comes when they get the ball between the lines, and that's through Iniesta or Messi.

"They have to get the best from the transitions and not allow Messi to get the ball between the lines. The only two or three times Barcelona had chances in the first leg was when that happened."

Much has been debated about whether Eden Hazard, like in the first-leg, should be deployed as a false-nine. But Ayestaran believes the Belgian would suit better in his natural position.

"We've seen before how Hazard is more dangerous coming in off the left," he said. "Even in the last game when he started in the middle all the danger came when he was coming in off the left.

"It's more difficult to defend players coming inside, because the full-backs have to decide whether to follow or not. They leave a gap if they do follow, and if they don't they are given time on the ball.

"When they are coming from the middle, like what happened in the first leg, the centre-backs can close them down. That's why we decided in that game to play with a midfielder in a wide area, to come inside and create that superiority, with players who are comfortable on the ball."

On stopping Lionel Messi and Andreas Iniesta, Ayestaran added: "Messi is just one apart. He's going to be remembered for many, many years and when he is at the top of his game, you have no possibilities.

"Against Messi, you have to try to be really well-organised, cover each other, shuffle across to deny him space. If you do that well, he's still able to triumph past all these difficulties you put in front of him.

"If Iniesta is injured, Chelsea's chances are a lot better. If Iniesta is not fit, it will leave Messi having to come and get the ball, and that will lessen the danger because someone like Paulinho will have to fill in.

"He's not a runner, he arrives late into the box. Barcelona will really miss Iniesta if he is not fit."