McGrath driven by the dream of claiming a unique double
Jack McGrath was talking about Leinster when it could have been the Scarlets.
"The most dangerous thing about something is being unpredictable," he said.
"We don't want another team to know what we are going to do at all times because they can just plan it out for their whole week.
"If we have a few aces up our sleeves throughout the game that teams don't see coming, it is much harder to defend. It ultimately means we can put them under more pressure."
Stuart Lancaster's push for more unstructured rugby to Leinster's game has empowered all the players to add a touch of unpredictability.
Loose-head McGrath was the 'ace up Leinster's sleeve' for Jack Conan's try against Munster in the PRO14 semi-final.
He set up for a straight-ahead drive into Rhys Marshall with Jordi Murphy on the premises for a latch.
The picture presented convinced Sam Arnold that was what was coming.
The centre abandoned his post to jam in on McGrath and the prop's slip-ball back inside put James Lowe through a hole where Arnold should have been.
Leinster's smart play revolves around more than one option off the ball handler.
The same could be said of Scarlets, with their danger usually coming further out where duping defenders can put their fastest men in position to gobble up the yards.
Once they get in behind the first line of defence, all bets are off as the support runners flood through, with scrum-half Gareth Davies almost always handy.
"To play against us is unpredictable and they are unpredictable," said McGrath.
When Scarlets gash, it can be a terminal cut that causes bleeding all over the place.
Glasgow had taken control of Conference A from early in the season and kept the foot down to draw a home semi-final at Scotstoun.
Their coach, Dave Rennie, would have methodically planned how to coral and contain the Welsh club.
Their fatal flaw was to get drawn into a shootout in which Scarlets' scrum and scramble defence were the superior factors between two high-powered attacks.
"They pretty much did to Glasgow at the weekend what they did to us last year," recalled McGrath. "We overplayed in key areas and they forced mistakes and scored some good tries.
"All their players like to play and it is going to be no different this weekend."
Leinster have alluded to the wrinkles they will have to add to what they did in the Champions Cup semi-final.
In reality, the same game plan of winning the ball and keeping it by blitzing the ruck with the odd tweak here and there will go a long way towards doubling up.
"I am around long enough to remember when we won a Heineken Cup at the time and then going to a final and not being able to get over the line.
"There is that experience and bit of bitterness," said McGrath.
"A lot of great guys have walked through that door at Leinster and not done that (the double). That is definitely a driving factor."