England, currently top of the RBS 6 Nations Championship table on points difference from unbeaten title rivals Ireland, will arrive at Lansdowne Road next Sunday for an ultimate winner-takes-all encounter.
On all three previous final-hurdle challenges during Clive Woodward's tenure - at Wembley, Murrayfield and latterly, Lansdowne Road - they failed to land the biggest prize in European rugby.
England's midfield talisman Greenwood knows it will require a Herculean effort to deny resurgent Ireland their first championship clean sweep since the days of Jackie Kyle and Karl Mullen in 1948.
"It is an enormous task," said the Harlequins star. "We seem to have had a bit of a Jekyll and Hyde-style character to our performances this year."
England set up a Grand Slam showdown by swamping Scotland 40-9 - their 12th triumph from the last 13 Calcutta Cup Tests.
"Some of our performance was eight out of 10, and some of it was five out of 10," Greenwood added.
"Next Sunday, it will be a case of here comes the kitchen sink, but Ireland are much better than that. They are a footballing side, and we appreciate the enormity of the encounter. It's an FA Cup final, a one-off game."