The defeat comes just two days after England's narrow loss to India in the final of the Champions Trophy and Morgan is much happier now than he was after that game.
"Obviously it's not as frustrating as the other day, that was a huge opportunity missed whereas tonight was a great performance with plenty of positives to take from it, and moving forward with the young guys that we have it's a great prospect," Morgan told Sky Sports News.
England could be boosted by the return of Kevin Pietersen for the second clash against the Black Caps on Thursday and Morgan added that he would "love" to have KP back.
"We'd obviously love to have him back. We'll discuss where he fits into the side," he said.
Thursday's match is also at The Oval and you can follow live updates here on Sports Mole from around 6pm.