Bayern vs Olympiacos

Arsenal vs Sheffield United English Premier League Unai Emery faces a big call this afternoon over whether to stick or twist with the same Arsenal defence which won at Newcastle United.

Arsenal vs Sheffield United Live

The Gunners secured a 1-0 victory at St James' Park last Sunday to kick off the new Premier League season with three point - and, crucially, a clean sheet away from home.

Defence was a constant frustration for Emery last term, with Arsenal's impressive attack so often let down by basic errors at the back.

David Luiz has been brought in from Chelsea to cover the departure of former captain Laurent Koscielny, but the Brazilian may have to wait for his first Arsenal start with Emery unlikely to alter the defence which shut out Newcastle on Tyneside.

That should see Sokratis Papastathopoulos and Calum Chambers retain their centre-back roles, while Ainsley Maitland-Niles and Nacho Monreal at full-back.

Mesut Ozil and Sead Kolasinac are available after being withdrawn from duty last week due to a security situation being investigated by the police.

The duo, who escaped unhurt after an attempted carjacking last month, were not in the squad at Newcastle United last weekend due to "further security incidents", but Emery says the pair are "good options" to face Burnley.

Emery also confirmed that he will make a decision on whether to start club-record signing Nicolas Pepe after training on Friday.

Lucas Torreira may come in to midfield with Granit Xhaka an injury doubt, while Alexandre Lacazette should start up front after recovering from injury.