Seamus Coleman has urged Republic of Ireland defender Shane Duffy's critics to cut him some slack on the eve of his country's new World Cup qualifying campaign.

Duffy met up with his international team-mates having lost his place at Celtic – where he is on loan from Brighton – having struggled for form, but will hope to start his country's opening qualifier against Serbia in Belgrade on Wednesday night.

The 29-year-old has worn the captain's armband in Coleman's recent absence, and the Everton full-back is in little doubt as to what he will contribute if he is selected by manager Stephen Kenny.

Coleman said: "Shane Duffy is a warrior, Shane Duffy is a leader, I think all us Irish people have seen that over the years with his performances.

"Listen, he's not had the easiest time over in Scotland. I've watched the games that he's played and I don't think Shane Duffy is the reason why things aren't going the way they wanted up there, there's a lot of other reasons, I'm sure, for it.

"I don't know if he'll mind me saying this or not, but Shane Duffy's dad passed away last summer and not long after his dad died, he was straight back on a plane for Brighton and straight up to Celtic, and they're the little things that I don't think people take into account.

"I don't know if he will even have had the opportunity to mourn his dad properly. This football bubble is so important – 'Yeah, you've got to get back to work, you've got to get back to Brighton...'.

"For me, a lot of that has to be taken into account too, and we all need to bear that in mind because the lad would do anything for his club or his country.

"He doesn't sulk, he's a great character around the place, he's a warrior and he had a tough time, and jumped on a plane to get back to work, maybe quicker than most people would, so I think Shane Duffy has done enough.

"He has enough credit in the bank for his country for us to keep supporting him."

Should Duffy get the nod, he will line up in front of 21-year-old keeper Mark Travers, who will win his senior third cap with Darren Randolph sidelined by injury.

But with Ireland having failed to score in the last seven of their eight games to date under Kenny, none of which they have won, there will be as much emphasis placed on what happens at the other end of the pitch.

The manager said: "You look at a team like Liverpool, with the forwards that they have, they went a right number of games without scoring. It can happen to a team.

"I think it will be something that we will address soon enough. We need to address it quickly and we've got the game against Serbia.

"We've hit the post quite a bit and hit the bar, so we need to just take our chances when they come."