The pace-spin combination was at their destructive best when they skittled co-hosts Bangladesh for their lowest ever ODI total of 58, a feat that angered local fans who ended up hurling stones at the West Indies bus following the match in Dhaka.
Safe in the knowledge that they will not face any local backlash following their next match, the Caribbeans will be keen to crush Ireland to boost their chances of a quarter-final place from a wide open Group B.
West Indies had started their campaign on a sour note, suffering a comprehensive defeat by South Africa but they came back all guns blazing and swatted away the Netherlands and Bangladesh in their next two matches.
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While paceman Roach and spinner Benn have excelled with the ball - taking 18 wickets between them in three matches - former captain Chris Gayle has caused havoc with the bat.
The explosive Gayle and Kieron Pollard are well backed up by the experience of Ramnaresh Sarwan and Shivnarine Chanderpaul in the batting department.
"We will put our best foot forward when we play against Ireland later this week," Roach, fourth on the wicket-taker's list with 10 victims, said.
"They are a good team and they are playing good cricket, so we are not taking things for granted and will play our best game against them.
"We are going to go out there and give our best shot."
"Best shot" will be an absolute necessity as the Caribbeans play their last two matches against England and co-hosts India.
The Caribbeans, currently with four points from three matches, would, however, have to guard against complacency when playing a rapidly improving Ireland side.
The Irish have already caused the first major upset in the showpiece event with a three-wicket victory over England and would like to keep their quarter-final hopes alive with a win against West Indies.
The performance against England catapulted Ireland to the 10th spot in the ODI rankings, ahead of Zimbabwe.
Their spirited display with the ball and on the field against India Sunday also did not go unnoticed and earned them rich praise from India captain Mahendra Singh Dhoni.
"We've got three games left and there's no reason we can't beat any of the three teams we're playing," said Irish skipper William Porterfield.
Ireland, with two points from three matches, will play South Africa and the Netherlands in their last two group matches.
