Wales manager Chris Coleman has admitted that Luka Modric represents the greatest danger to his side's chances of beating Croatia tonight.
Coleman has Gareth Bale fit for the Liberty Stadium clash and believes that the two players are both "unstoppable" at their best.
After beating Scotland 2-1 on Friday night, Coleman believes that his team can earn back-to-back victories if Modric does not perform.
He told The Sun: "On his day Modric is unstoppable, just like our boy Gareth.
"Croatia have a lot of good players playing for top clubs around Europe and the icing on the cake is Luka Modric. Sometimes when great players, the top, top players, are on form it's very difficult to stop. It is just genius.
"Sam Allardyce summed it up after West Ham played Tottenham at Upton Park. You can work as much as you like on stopping a player. But if they have the capacity to do what Bale and Modric can do, pass from 60 yards or scoring the goal Modric scored at Old Trafford for Real Madrid, there is nothing you can do. When they are in the mood, on that form, it is very difficult."
Wales are without Aaron Ramsey through suspension for tonight's World Cup qualifier in Swansea.