Burnley set for toughest test yet on trip to Athens
Atalanta can establish commanding lead over Danish leaders Copenhagen
Europa League playoff round first legs
From 5pm Thursday
Having overcome Aberdeen and Istanbul Basaksehir, the Premier League side need to clear one more obstacle to seal a place in the group stage.
However, Olympiakos are warm favourites to win the first leg and are no bigger than 8-11 to win the tie.
The Greeks finished third in their domestic league last season but they are seasoned European campaigners and have featured in the Champions League group stage in six of the last seven seasons.
Burnley boss Sean Dyche has stressed that the league is his main priority and is preparing to make changes.
However, his options are boosted by the availability of striker Matej Vydra and goalkeeper Tom Heaton, who have been added to the Clarets' Europa League squad.
Celtic have dropped into the Europa League after losing a Champions League third qualifying round tie to AEK Athens but they are hot favourites to win their playoff round tie against Lithuanian champions Suduva.
The Bhoys may be boosted by the return of Dedryck Boyata, who has returned to first-team training.
Boyata, a reported transfer target for Seville, has not featured for Celtic this season.
The Gers have passed three tests - getting past Macedonian side Shkupi, Croatian outfit Osijek and Slovenians Maribor – and are odds-on to establish a first-leg lead over Ufa before making the long trip to Bashkortostan next week.
Rangers will be without winger Jamie Murphy (knee) and defensive duo Connor Goldson and Nikola Katic are injury doubts after taking heavy knocks at the weekend.
However, the best bets are in games not involving British sides. Atalanta impressed in last season's Europa League, posting wins against Everton and Lyon, and can establish a commanding advantage over FC Copenhagen after the first leg in Bergamo.
The Italians breezed through the last round, beating Hapoel 6-1 on aggregate, and should have too much quality for the Danish league leaders.
Steaua Bucharest have conceded just one goal in four Europa League matches this season and their solid defence can provide the foundation for a decent result against Rapid Vienna in the Austrian capital.
The markets favour Rapid, who are evens for a first-leg victory despite winning just one of their last five games.
Steaua are unbeaten in eight matches and look value to secure a draw or better in Vienna.
Atalanta -1 on Asian handicap
2pts 17-20 bet365
Steaua Bucharest or draw double chance
2pts 4-5 Sky Bet
Read Racing Post Sport every day for no-nonsense previews and expert sports betting tips
Follow us on Twitter @racingpostsport
Like us on Facebook RacingPostSport