Leinster coach Michael was left counting the cost of his side's error count as they collapsed to 33-9 loss at the hands of Celtic League leaders Munster.
The Australian supremo was fuming as the province's red-shirted rivals were allowed to tally up five tries - four in the second half - to confirm their superiority in front of a 7,500-strong Musgrave Park crowd.
Cheika, who watched captain Felipe Contepomi kick Leinster's only points, said: "If you give good opposition the kind of opportunities our mistakes allowed them, they will kill you. They scored 21 points as a result of our errors. We were okay in the first 20 minutes but then mistakes combined with indiscipline cost us."
Leinster have an ideal chance to make amends and learn from those mistakes over the next two Saturdays as their focus shifts to their new European home of the RDS in Dublin.
Next Saturday's Celtic league tie against Cardiff will be played at the venue as a dress rehearsal for the following Saturday's Heineken Cup opener against Bath.
Munster coach Declan Kidney predictably played down the significance of his side's bonus point win - a success which sees them sitting one point clear of Ulster at the top of the league table.
Munster are idle until Friday week when they travel to Sale to open their Heineken Cup campaign. Kidney is hopeful the men in red can transfer their form from the league to European competition.
"The Celtic League is a very tough, physical place to play. Players were at it hammer and tongs and I don't see any of them holding back in any of the matches," said Kidney.
"Our best chance of doing well in the Heineken Cup is if we pay proper respect to all the games instead of going from a certain type of performance up to a much higher performance in a few weeks.
"Today (Sunday) was encouraging but we would hope to maintain that level no matter what competition we're in."
Late inclusions in the side - Federico Pucciariello, Barry Murphy and Tomas O'Leary - certainly gave the Corkman some food for thought over the next few days. With first choice scrum half Peter Stringer sidelined, the 21-year-old O'Leary, who impressed with his sniping runs and speedy pass against Leinster, could start against Sale next week for what would be his third senior cap for the province.