Ukraine club Metalist Kharkiv remain barred from the Champions League after the rejection of an appeal against a ban for links to match-fixing.
Metalist were due to face German side Schalke next Wednesday in the first leg of the competition's play-off round.
Uefa had announced their place would go to Greek club PAOK Thessaloniki,
whom they beat in qualifying last week.
"The Uefa decision remains in force," said the Court of Arbitration for Sport (Cas), which Metalist had appealed to.
Uefa charged Metalist after Cas upheld a five-year ban against sporting director Yevhen Krasnikov for alleged match-fixing, but the club took up an option of appealing to Cas.
The ban, by the Ukrainian Football Federation, was for alleged involvement in the fixing of a 2008 Ukrainian league match with Karpaty Lviv.
Uefa disqualified the club from European competitions for the 2013-14 season but if Metalist submitted an urgent appeal to Cas, the court could have suspended sanctions, allowing the club's debut Champions League campaign to continue.
Arsenal's Champions League play-off opponents
Fenerbahce were banned from competing in Europe in June for their involvement in domestic match-fixing
but have appealed to Cas.
Cas says a final decision in that case will be made by 28 August, after the second leg of the play-off, but Uefa says no decision has yet been made regarding what would happen if Fenerbahce won the tie and lost their appeal.