BURNLEY walk into the unknown tonight as they face Greek giants Olympiakos in the first leg of their Europa League play-off tie.

The Clarets are at the Karaiskasis Stadium for the game against a side who had won seven successive Greek Super League titles until they finished third last season.

We asked Greek football expert Antonis Tsirakis for the lowdown on Olympiakos.

Olympiakos’ run of seven straight titles came to an end last season, so how was the season judged and what went wrong for them?

Every year that Olympiacos fail to win the championship, it's like a disaster for them. As for what went wrong, they had a big problem with Besnik Hasi.

He wasn't good enough. And the other problem was the atmosphere generally in the locker room.

What are the expectations this season?

As for this season, if you ask an Olympiacos fan they will tell you that they have to win the title. For me, it's not easy. PAOK have a very good team, AEK are champions.

But for Olympiacos the expectations every year is to win the title. And they want to qualify to Europa League group stage.

There have been a lot of changes this year in terms of coaches and players. Are the new team gelling or are they still an unknown quantity?

As for this season, if you ask an Olympiacos fan they will tell you that they have to win the title. For me, it's not easy.

PAOK have a very good team, AEK are champions. But for Olympiacos the expectations every year is to win the title. And they want to qualify for the Europa League group stage.

Who are the key players that Burnley will have to watch out for?

As a Premier League fan, I've watched many Burnley games. Their two full backs (no matter who is going to play) are not that strong. So, I expect that Daniel Podence and Lazoros Christodoulopoulos will cause them troubles.

Kostas Fortounis is also a key player but he is not consistent. He can be top in one game and awful in the second.

Will Olympiakos be playing their strongest possible team to get through to the Europa League group stages?

For Olympiacos is vital - economically - to get through to the Europa League group stages.

It's not negotiable that they will play with their strongest squad. If they fail to qualify, who knows what will follow for the manager and some players...