This was not a match Munster had all their own way. Kiwi kicker Ben Blair missed his first pot at goal after two minutes, but opened the scoring just a minute later with a 40 metre shot from the right hand side.
Munster chose to kick to the corner with their first penalty, and moments later were held up as the famous pack got into their stride. From the resulting scrum No.8 Denis Leamy muscled his way through to score the game's opening try, which O'Gara converted.
Munster's positive ambition was displayed again at their next penalty opportunity when captain Paul O'Connell signalled O'Gara to kick to the corner. Munster's pack powered up - but were held up as they attacked the line.
Munster's second try came from a bit of lightening thinking from Munster's scrum half Peter Stringer. He forced his opposite number to kick into touch just 10 metres from his own line, and took the throw immediately to Leamy who had the simple task of running a short distance for his second try of the game. O'Gara added the extras.
Yet just four minutes later Blair responded with his second penalty kick of the match to keep his side in touch with the Heineken Cup champions. It was significant that at Munster's next penalty O'Connell signalled O'Gara to notch three points, which he obliged.
With the sides preparing for half-time, Jamie Robinson silenced the home fans as he intercepted a loose Munster pass, and chased his own kick 50 metres to score; when Blair added the extra two points the Blues were back in the match.
However, the Blues are so often their own worst enemy; when O'Gara scored the penalty that was granted for Martyn Williams's yellow card for killing the ball the Blues looked like they may press the self destruct button again.
When Munster centre Barry Murphy scored the opening try of the second half after 48 minutes, the home fans' faith in their side was restored - as was the two-score advantage.
Incredibly, the Blues first foray into Munster territory in the second period ended in a five point score. Gary Powell found himself fifteen metres out, and offloaded in the tackle to Williams who saw Blair in space to his left, and he fed replacement Mark Lewis to score.
Moments later the Blues squandered a chance to get themselves right back in the match. Jamie Robinson couldn't hang on to Blair's pass when the break was begging, and Munster took long hard looks at themselves.
The errors still came from the European champions and despite spending the majority of the final quarter in the Cardiff red zone, the red machine took until the fifth minute of extra time to breach the line to make the result safe and earn a bonus point - but only just.