West Ham’s first match at the Olympic Stadium will be against either Shakhtyor Soligorsk of Belarus or Slovenian side Domzale.
The Hammers have taken up residence in the revamped London 2012 venue after leaving Upton Park, their home for over 100 years, at the end of last season.
Slaven Bilic’s side are taking on Italian giants Juventus in a glamour friendly to mark the opening of their new 60,000-seater ground in Stratford on Sunday, August 7.
But they will actually take to the field for the first time in their new ground before that, with West Ham’s first fixture to come against the winner of the second-round qualifier, which is currently poised at 1-1 between the Belarusian and Slovenian sides.
West Ham’s home leg is due to take place on 28 July, but the club have made an official request to UEFA to reverse the dates of the two legs, as the stadium is being used for the London Anniversary Games on 22 and 23 July. The second leg is scheduled for 4 August.
The Hammers’ first home game in the Premier League will then be against Bournemouth on 21 August.
A club issued a statement explaining their request to reverse the tie, which read: “In order to give Stadium owners E20 Stadium LLP as much time as possible to prepare the arena for its first taste of European football, the Club have today made official representation to request that the fixture be reversed.
“If successful, Shakhtyor Soligorsk of Belarus or NK Domžale of Slovenia will visit Queen Elizabeth Olympic Park for the return leg on Thursday 4 August.
“Owing to the date of the Europa League fixture, the Club has had to agree to work to a capacity of 54,000 for the Hammers’ first two fixtures at London Stadium. And, given the proximity of the Anniversary Games [22-23 July] to those opening two West Ham games, Stadium owners E20 Stadium PLP are doing their utmost to prepare the venue fully into football mode accordingly.
“On behalf of its supporters, the Club went to great lengths in contractual negotiations with E20 Stadium LLP to ensure that the Stadium would be fully ready for the first two fixtures, in order to accommodate as many supporters as possible and offer the best matchday experience.
“This is a necessary step for the ramp up to the Stadium opening in full football mode at its full 60,000 capacity for the eagerly-awaited opening Premier League fixture against AFC Bournemouth on Sunday 21 August.”
West Ham were forced into playing a Europa League qualifier after being pipped for sixth place in the Premier League by Southampton on the final day of last season.
They featured in the qualifying stages last season by virtue of the Fair Play League, but Bilic fielded youngsters and fringe players as they bowed out to Romanian side Astra Giurgiu in the third round.
Bilic has vowed to take this season’s competition more seriously, however, and has already bolstered his squad with Havard Nordtveit, Sofiane Feghouli, Gokhan Tore and Ashley Fletcher.
Meanwhile, other British-based clubs in the qualifying rounds include Hibernian will take on German side Hertha Berlin if the Edinburgh outfit can overturn a 1-0 first-leg deficit against Danish outfit Brondby.
City rivals Hearts, whose first leg in Malta ended 0-0 against Birkirkara, will be aiming to set up a tie against Russian side Krasnodar.
Aberdeen, who are 3-0 up against Latvian side Ventspils, will face Maribor of Slovenia or Bulgarian side Levski Sofia, providing the Dons avoid trouble in their second leg.
Northern Irish side Cliftonville will take on Spartak Moscow if they can come back from a 3-2 first-leg defeat against Cypriots AEK Larnaca.
Cork City, who are tied at 1-1 with Swedish side Hacken, have been drawn against either Belgium’s Genk or Podgorica of Montenegro.
If Welsh minnows Connah’s Quay come from 1-0 down against Vojvodina they could face Ireland’s St Patrick’s Athletic, who drew 1-1 with Dinamo Minsk in their first leg.