Warren Gatland’s Welsh side face a group decider against Australia at Twickenham on Saturday, with the winners likely to face either Scotland or Japan in the quarter-finals, and the losers two-time world champions South Africa.
Harlequins-bound Roberts conceded the sense of World Cup devastation could easily have been on the other foot had England not surrendered 10-point leads on two occasions in the second-half of their 28-25 defeat to Wales at Twickenham.
“It’s a brutal pool and it was always going to be one of three teams missing out,” said Roberts. “That’s what makes the World Cup so exciting, there are such fine margins.
“The question is being asked of England not qualifying. We beat them by three points. We could have lost that game and England could have been going through and the questions asked of us.
“I feel sympathy with the difficulty of the group and how ruthless it has been. It is disappointing as the host nation, and not to see them through is hard for the fans as much as anyone.”
Wales’ progression to the last eight was confirmed on Saturday as England were dispatched 33-13 by Australia, a match which Roberts watched with friends at Rosslyn Park Rugby Club.
“I was shaking for 80 minutes. It was like playing a game, though not expending as much energy,” added Roberts. “I sat on the sofa in front of the big screen and didn’t move.
“When it got to 20-13, I am sure the whole of Wales was panicking a bit, but Australia came through so we are delighted to get through to the quarters. But it doesn’t take the importance off this week. All is still up for grabs, it’s a huge game.”