Ernesto Valverde must help Barcelona keep Manchester United at bay or indeed kill them off, extinguishing their hopes of progress in the Champions League on Tuesday night.

Camp Nou plays host to the English outfit who must overturn a 1-0 deficit following victory for the Catalans at Old Trafford last week.

Here, we look at the key tactics Valverde may employ.

Click here to read United’s key tactics.

DEMBELE EFFECT

Ousmane Dembele’s likely return to the starting line-up should see his pace and trickery on the left wing stretch United’s defence, creating space for Lionel Messi when he drifts inside.

The Argentine, along with Luis Suarez, definitely missed the scrambling effect the 21-year-old has on defences during his injury layoff.

The Frenchman’s threat means Jordi Alba’s marauding runs forward from full-back carry more weight as well, bringing his cut-backs for Messi into play. As the game progresses and United begin to commit more numbers forward, Dembele’s searing pace will prove crucial on the counter-attack, something that they sorely lacked during the closing stages at Old Trafford.

RAKITIC ROLE

Given that United only had 35 per cent of possession at home, it’s conceivable that they may enjoy even less at Camp Nou. For their part, Barcelona must drive home that advantage and ask more questions of the defence.

With Dembele likely to push up with Messi and Suarez in possession, Ivan Rakitic must support the front three in the final third.

During a prolonged spell of controlled passing, the Croatian can take up a number 10 role in behind the attack to create more problems for the visitors. Sergi Roberto can then push up and tuck inside to sit alongside Arthur and Sergio Busquets, maintaining pressure on United.