Vitória SC coach Rui Vitória enjoyed a continental debut to remember as his side ran out comfortable 4-0 victors against HNK Rijeka.
Centre-back Abdoulaye Ba broke the deadlock nine minutes before the break and when Nii Plange, another on-loan player, tapped in soon after the restart they were well on their way. Further goals from Moussa Maazou and André André sank a Croatian side that had made such impressive progress since entering the UEFA Europa League in the second qualifying round.
It was Rijeka who had the first opening of the evening, striker Leon Benko firing straight at Abdoulaye after a defensive mishap. Guimarães replied with verve, captain Moreno forcing Ivan Vargić into a parried save that Moussa Maazou ought to have put away; he fired wide of the empty net.
Plange got in the act, having a vicious shot pushed away by Vargić and then came the opener. Maazou had a shot cleared off the line by Luka Marić and from the subsequent corner, André André headed into the path of Abdoulaye, on loan from FC Porto, who directed beyond Vargić.
The second half was only three minutes old when Guimarães doubled their lead. Maazou got away on the right wing and delivered a cross from the byline right into the path of Plange; the Sporting Clube de Portugal loanee applied the tap-in.
Now the shackles were really off as Guimarães cut loose. The dynamic Maazou got the goal he deserved, slotting in a penalty after Marić had tripped André André. Four minutes from time it was 4-0 as André André seized on the rebound after a fierce shot, setting the seal on the Portuguese side's biggest win in UEFA club competition.