The Irishman’s characteristically clinical penalty seven minutes into first leg stoppage time at Pittodrie a fortnight ago proved the decisive moment in a 3-2 aggregate win against SC Fola Esch.
The 1-0 second leg defeat that followed against the part-timers may have been one of the most embarrassing results in the club’s history but crucially, the Dons are still in the competition.
Now Rooney and his team-mates are determined to make the most of that situation starting when another of the continent’s lesser known sides, FK Ventspils, visit Pittodrie tonight.
The striker has warned their Latvian opponents only have to look back to this time last year and the way Aberdeen responded to a close call against Macedonia’s Shkendija to see what they are capable of.
He admits: “We were very down and disappointed after the Fola game due to the performance. Now we will use that loss as motivation going forward. I have been at this club for two and a half years and there have not been many performances like the one against Fola.
“The main thing in cup competition is progressing to the next round and we are confident going into the tie with Ventspils.
“Last year we didn’t get through too easily in the first round against Shkendija where we didn’t play good football but then we went over to Croatia in the second round and produced a great performance to beat a good Rijeka team 3-0.
“Ventspils look a good, well organised side and they will be well up for it so we expect a difficult game but if we reach the performance levels we know we are capable of then we can match anyone.” Aberdeen’s chances of success tonight are boosted by the fact Rooney is ready to start his first competitive game since picking up a serious injury at Inverness back in mid- February.
Losing their top scorer with a muscle tear ripped the Dons’ title challenge to pieces as they only won five of their last 12 Premiership games without him.
He wasn’t ready to start either of the first round matches but a run-out and a goal in a 4-2 win against East Fife last weekend means he’s raring to go tonight.
That’s bad news for Ventspils as Rooney scored five of Aberdeen’s goals in an 8-0 aggregate win against Daugava Riga, the last Latvian opposition they faced just two years ago.
He added:”I am feeling sharper and fitter and it was good to get that start and more game time against East Fife.
“There have not been any problems or setbacks with the injury and it is probably going better than I expected at this stage. I have featured in the first two European games and also got off the mark with a penalty against Fola.
“Hopefully I am nearly 100 per cent and I am good to go from the start against Ventspils if called upon.”
The Latvians defeated Vikingur of the Faroe Islands 4-0 on aggregate in the previous round but come into the tie on a poor run of domestic form.
They are midway through their season and sit third in the table after losing three of their last four matches including a first home defeat in 20 games last Sunday.
Their English manager Paul Ashworth said:”That defeat was bad for us in the Latvian league but perhaps it can also be an advantage in Europe.
“We will approach the Aberdeen match angered and mobilised. It will not undermine our spirit on the eve of what will be a very difficult game.”