"He's a bit of a free spirit at times and we have to work hard on the sidelines to nail him down at times from a shape point of view and out of possession.

"But I think you've seen what he gives you in possession. We want him to play further forward at times, because when he does he goes into overdrive and speeds the game up. He's got genuine quality to hurt."

Richard Stearman headed the Blades into a first-half lead against the run of play and Oliver Norwood fired home their second from the edge of the area after being set up by Morrison.

Blades goalkeeper Simon Moore saved Adam Armstrong's early penalty, after Stearman had clipped Bradley Dack, but Blackburn substitute Sam Gallagher halved the deficit with a header in the 61st minute.

"Even though we weren't great, we weren't at our best, we've got a result," added Wilder, who made 10 changes after Saturday's home defeat to Leicester.

"We got through to the next round and the players will benefit from a really intense game of football."

Blackburn boss Tony Mowbray, who was sent to the stands in stoppage time by referee Geoff Eltringham, failed to attend his post-match press conference.

Mowbray, who made eight changes himself, saw his side control long spells of the match and pile on the pressure in the closing stages.

But the former Middlesbrough manager took exception to a challenge on one of his players and lost his temper as Eltringham approached him, before being shown a red card by the official.