It was the first time Ireland were unable to field the injured O’Driscoll and O’Connell for an RBS 6 Nations match since 2001.

Led by Rory Best, the Irish thrived in their absence with man of the match Donnacha Ryan, Stephen Ferris and Rob Kearney among the star performers.

“Sometimes you get a bit frustrated when Brian and Paul are out of the squad because some people seem to think you can’t tie your laces without them,” Lions lock O’Callaghan said.

“When you’re missing two guys of their calibre it gives opponents a bit of confidence.

“They smell blood in the water and that becomes their focus for the week.

“It’s important that when there’s a bit of a void other people step up and that’s what happened throughout the team against Scotland.

“It’s good for ourselves to get a result like that.”

Best, Eoin Reddan, Andrew Trimble and Fergus McFadden ran in tries and Jonathan Sexton kicked 12 points in an entertaining encounter that was only settled in the last 10 minutes.

The result has no impact on the title race as Ireland’s pursuit of the crown ended following their draw with France, but it ensures they will descend on Twickenham in high spirits.

The climax of the tournament against England will also conclude their gruelling workload of four Tests in 22 days, a schedule enforced by the postponement of their original game against France.

Three players – O’Connell, Sean O’Brien and Conor Murray – were lost in the aftermath of Paris and O’Callaghan admits the attrition rate is being felt in the dressing room.

“England is a huge ask now. As a player you don’t mind going four games on the bounce but it does take its toll,” he said.

“It’s been a bit unfair on us, but that’s the way it is. It’s always tough after a World Cup year because you pretty much have two seasons in one year.

“We might not see the fallout until the end of the season, but we have bangs and knocks that are unusual for this time of the year.”

Ireland will head to London as the championship’s most clinical side – they have scored 13 tries – and with a defence that has stiffened since their opening-weekend loss to Wales.

“You have to give credit to the system that (defence coach) Les Kiss has devised for us,” O’Callaghan said.

“It’s nearly an offensive weapon in that when they have the ball we look to take them and get something out of it.

“We started off really poorly in terms of our line speed. Les was saying that our performance against France can’t be a one-off and he will be happy enough with what we showed against Scotland.

“Stephen Ferris led it and is doing an incredible job, taking the line up and rolling fellas.”

Ireland will finish the Six Nations in mid-table, ruing a championship haunted by bad luck.

But they only have themselves for losing a game they should have won against Wales before surrendering a 17-6 interval lead to draw in Paris.

Had they been just a little more ruthless, they would be heading to Twickenham with a Grand Slam at stake.

“Unfortunately, that’s sport. You get good days and bad days,” Best said.

“Against Wales it was bitterly disappointing but the bottom line is we were six points up with eight minutes to go, at home, and we weren’t able to close that out.

“In France, we were 17-6 up at half-time and didn’t score a point in the second half.

“We produced a good performance against Scotland and that’s what we wanted, but we’re disappointed not to have won all of our games to date.”