O'Sullivan has doubts about Irish at Twickers
Eddie O'Sullivan doubts Ireland have enough "shots in the locker" to take down England.
"It's going to be a massive challenge.
"On the face of it, looking at the injuries, looking at the way England are gradually taking the incremental steps under Eddie Jones, I'm not sure we have the shots in the locker, at the moment," he told Sunshine Radio.
The facts are England are on a roll from two wins and Ireland are on the back-foot after failing to win in the first two rounds.
"This season was always going to hinge on Twickenham," said the former Ireland coach.
"Where we are now, if we win there, it gets the season somewhat back on track because it puts us in a position to finish out with two more wins at home.
"That would put us in with a shout of the championship to finish first, second or third.
"If we lose, we are going to be in the bottom half of the table which is not where we want to be."
Either way, England were always going to be Ireland's barometer. "This game is the fulcrum of the season for us," he added.
"It's a fairly intimidating place.
"It's hard to get a result and I think we really need our ducks in-a-row to get a result."
O'Sullivan knows what he is talking about.
He was the architect behind Ireland's wins there in 2004 and 2006.