"We must have an advantage because the confidence must be high, particularly among the bowlers," he said.
"As for our batsmen, like Mark Butcher, if you take a bit of batteringand then win like we did that has to be a huge advantage.
"But when we get to Trinidad we have to play some more good cricket. It's as simple as that."
It may help, rather than hinder England, that Fletcher is on his first tour of the Caribbean. The coach has no preconceived ideas of what pitch conditions to expect on each island and will go to Queens Park Oval with an open mind about team selection.
That could even mean a change of personnel come Friday.
"You have to play things day by day," Fletcher said. "We just want to see how the players react. We'll make a plan and an adjustment if required."
It is a totally safe bet, though, that, barring an injury, Harmison will lead England's attack again.
Sunday's seven-wicket demolition job catapulted the big Durham paceman into the top 10 according to the latest world rankings for Test bowlers.
As Fletcher says, he now puts the "frighteners" on opposition batsmen, and that's pretty to watch for England.
