Emlyn Mulligan has pinpointed three Dublin forwards who remain crucial to the county's drive for five, despite the attacking riches available to Jim Gavin.

The reigning All-Ireland champions eased past Roscommon in their second Super 8s outing at Croke Park, cruising to a 2-26 to 0-14 win to secure their place in the All-Ireland semi-finals.

The Dubs had 10 different scorers, but Mulligan felt the quality of their performance dipped in the second half when Gavin withdrew key forwards Con O'Callaghan, Paul Mannion and Ciarán Kilkenny.

The trio combined for a total of seven points against the Connacht champions, but Mulligan pointed to the fact their general play is equally important to Dublin's gameplan. 

"One thing we did notice, it just shows how important Con O'Callaghan, Mannion and the likes of Ciarán Kilkenny are," Mulligan said.

"I think we take for granted how good they are, because when they were taken off it showed I suppose a bit of a dip, and a blip in Dublin's performance. Just their natural ability for showing for ball, their workrate, everything about them.

Ciarán Kilkenny was replaced by Kevin McManamon in the second half

"I think we'll judge them (Dublin) more on the first half rather than the second half. It was a foregone conclusion that Dublin were going to win the game and we spoke beforehand of how much (they would win by)."

The Leitrim forward was also keen to stress the quality of Dublin's performance against a team that have proved a handful for some of the country's top sides this season.

"They're not going to learn a massive amount but I think we have to give them the respect they deserve. Roscommon are the Connacht champions, they've beaten Galway and Mayo this year, they ran Tyrone close.

"It's very easy to say 'it's only Roscommon', but Dublin are phenomenal all over the pitch. They brought on lads off the bench, noticeably Paddy Small did himself no harm there today."