There is a sense of dissatisfaction in the Celtic camp as they head in to their game with the Highland side coming off the back of a Scottish Cup semi-final penalty shout-out defeat to Old Firm rivals Rangers.
Ronny Deila is under pressure as boss of the Glasgow club, and he will want his players to get the Rangers defeat quickly out of their system with a big home win over Ross County at Celtic Park this Sunday.
Schalk, however, doubts Celtic’s effectiveness as he claims his upcoming opponents aren't at the top of his game.
“They will be under a lot of pressure. They expect to win the title now as they've lost two cup runs and fans will really be putting them under pressure,” the striker told Herald Scotland.
"They will be really sharp and I think they'll want to get a couple of goals in the first half-hour to get a big win against us, but I don't think they are that good to outplay us on Sunday.”
"I think we can take advantage of their mistakes. Maybe they're a bit nervous because of the pressure and we can get a result."
Celtic currently hold an eight point lead of Aberdeen with five games remaining, while Ross County are level on points with St. Johnstone and one point short of Motherwell in fourth.
Ronny Deila’s men are sure-fire favourites to win the title, yet Sunday’s Scottish Cup semi-final defeat to Rangers has left a bitter taste in the mouth and the pressure is growing on their Norwegian boss.