The forthcoming seventh series will see the 600th person make their appearance in a bid to find romance, but the Croatian maître d' admits it hasn't all been plain sailing on the hit RTÉ show.
"Listen, I've had situations where it was like 'what did I give you?' I'd be 'Ah shut up man, what do you mean what did I give you, did you think there was something better?'
"Sometimes there was the situation where it was 'I deserve something better'. 'Well you deserve what we gave you - if you think you deserve something more, you can walk away but we did our best'.
"But that's a rude approach, when somebody gives you this kind of approach that says enough about them."
Despite some disasters there have been First Dates success, including that of the first couple to get engaged after appearing on the programme.
Carla and Shez announced their happy news during the summer after eight months together since meeting on the show.
"There has been a proposal, I have already been invited to the wedding.
"So let's see when the date is going to be, then we are going to bring the A-game, don't you worry," says Mateo.
He was not familiar with the old Blind Date show and its host Cilla Black, famous for her catchphrase 'Do I need to buy a new hat?' until we raised it,
"No, I wasn't familiar with that show. When certain people recognise me, they say 'oh there's your man from Blind Date', so I presume you are referring to that one," he said.
Most of the staff are back again, bar Ethan the cocktail waiter, who is taking a break for this series.
"I always remember the older ones, because they generally need a bit of a push and when it happens it's great to see that," he says of the daters who've passed through the doors of the restaurant in the Gibson Hotel in Dublin, where the show is filmed.
"I don't have favourites, I treat everybody the same. The older ones would be my favourite ones."
Among the daters on the first show in the new series are Jenny (57) from Tipperary and Seamus (59) from Meath; Geniele (30) from Rush, Co Dublin and pilot Shane (28) from Kildare, who both turn up nursing broken fingers; 26-year-old Corkonians Scott and Emma; and Órán (19), from Dublin, the 600th dater, hoping for a plus one with Luke (20) from Mayo.
Returning in future episodes will be the irrepressible Hughie Maughan, back for a second shot at love with Jason from Cork; Slovakian bombshell Katarina, who is hoping to blow the mind of Shane from Meath, and hairdresser Lain from Leeds, who arrives at the restaurant for a third time with a very special announcement.
Mateo is engaged to the love of his life, fellow Croatian Vjerana Visnjic, and they live near Dublin city centre with their two children, three-and-half year old Isabelle and Noah, who is eight months old.
Asked if he ever fancies any of the girls on the show, Mateo replies: "Listen, they all say this, and my lady is aware of that. Sometimes it's OK to look at the menu but I eat at home."
He hopes to marry when the children are a bit older and have the wedding in Croatia so their relatives can attend.
"When we get the chance and there's a bit of normality then of course we will get married at home," he confirms.
"I got back to Croatia recently, because I had to bring my little boy home. I had to bring him to my parents, it was lovely. I stayed for three weeks. My brother also has a little boy, which is a similar age to my girl. "
Mateo has lived in Ireland for nearly 15 years, having previously worked in his home country as well as Italy and Amsterdam.
"He is currently working in vegetarian restaurant Glas in Dublin, which was forced to close for long periods during lockdowns.
"Living at home was cool enough. I used my time for new studies and I tried to do a few other things to keep busy. Plus family time. I didn't cry about it," he says.
"The only thing was you have to go a little bit into your savings because the economy, it's not like a nine to five job, so you cannot work from home, which is an issue.
"After we went back to work there was no drama. But it was OK. We survived and we kept on moving."
Despite working in a vegetarian restaurant, Mateo concedes he is a meat eater.
"I do eat meat, tonnes of meat," he declares. "After working in a vegetarian restaurant any meat will do!
- First Dates is on RTÉ 2 on Thursday at 9.30pm.