Peter Hutton's side have traveled to Wales to take on Aberystwyth Town from 6.45pm, holding a 4-nil lead from the first leg.
Around 200 supporters have joined the Brandywell club on the road as Derry look to secure their place in the 2nd round of the competition against FC Shakhtyor Soligorsk of Belarus.
Derry will be without the services of Mark Timlin who has a hip injury while Ryan McBride has an ankle knock, Rory Patterson is suffering a dead leg and Dean Jarvis is carry a foot injury, they will all undergo late fitness tests.
Speaking ahead of this evening’s game City manager Peter Hutton said. "We are really looking forward to this game, although we had a convincing win at home last Thursday we are still reinforcing to the lads that this is only half time. We know we need to be very professional in our approach and see this game out to the final whistle. We expect Aberystwyth to come out all guns blazing and it's important how we handle that. We have been on a good run of late and the lads are looking to keep that going".
In the other games, It's nil-all going into this evening's second leg tie between Sligo Rovers and FK Banga at The Showgrounds and Dundalk have a 2-nil lead heading into their home tie against Jeunesse Esch at Oriel Park. That game gets underway at 7.45pm.