Rangers beat FC Midtjylland 4-2 in Denmark in the first leg of their third qualifying round clash to take a huge step towards the Europa League play-offs.
Alfredo Morelos headed Gers in front two minutes before the break and Joe Aribo and Nikola Katic struck twice inside four minutes in the second half to put the visitors in command.
The Danes struck two quickfire goals themselves and Rangers looked rattled but Scott Arfield's calm finish gave them a healthy lead with 20 minutes remaining.
The return leg at Ibrox takes place on Thursday, August 15, with the winner of the tie facing Legia Warsaw or Atromitos in the play-off round.
Aberdeen face an uphill task to progress in the Europa League after losing 2-0 in Rijeka.
Second-half goals from Antonio-Mirko Colak, a penalty, and Robert Muric undid good defensive work from the Scottish Premiership side.
Aberdeen - who had won 3-0 at Rijeka in the second qualifying round four years ago - created few chances on a cagey night in Croatia.
But Rijeka attacks were also largely blunted until Shay Logan grabbed Colak's shirt after 61 minutes when there appeared little danger.
Muric further tilted the tie Rijeka's way two minutes from time with a splendid low shot from 20 yards.