Porto and Celtic will not be part of this seasons UEFA Champions League after being dumped out of the competition in the qualifiers.
Porto was outwitted by Russian side Krasnodar on a dramatic night of qualifiers which saw the Portuguese giants rally in the second half, with Zé Luís and Luis Díaz pulling two goals back, but Krasnodar held on to progress to the final play-off round on away goals.
It is only the second time since winning the trophy under José Mourinho in 2004 that Porto has failed to reach the Champions League group stages.
Celtic crashed out after losing 4-3 at home to CFR Cluj. Celtic trailed 2-1 on aggregate at half-time after Ciprian Deac headed Cluj into the lead, but appeared to have turned the tie around with goals from James Forrest and Odsonne Edouard.
However, Billel Omrani converted a penalty after captain Scott Brown handled and, although Ryan Christie restored Celtic's lead again, Omrani and George Tucudean struck to earn Cluj a shock win.
Celtic have now exited the competition at this stage in successive seasons, after losing to AEK Athens the last term.
Last season’s semi-finalists Ajax were given a scare by Greek champions PAOK Salonika before squeezing through to the final qualifying round. After a 2-2 draw in the first leg, PAOK took the lead in Amsterdam through Diego Biseswar.
Dusan Tadic missed a penalty, but scored a second to bring Ajax level on the night, and ahead on away goals. Nicolás Tagliafico then scored a header with 10 minutes to go to put Ajax 4-3 up on aggregate, before a second Tadic penalty saw the hosts through despite Biseswar’s second goal in stoppage time.
Ajax will face Cyprus’s Apoel in the play-offs after they overturned a 2-1 first-leg deficit to defeat Qarabag with a 2-0 victory in Azerbaijan.
Elsewhere, Club Brugge edged out Dynamo Kyiv after a frantic finale, the Belgian side prevailing 4-3 on aggregate after a 3-3 draw – with three goals coming in the last five minutes.