Hearts captain Christophe Berra described Inverness as "no mugs" ahead of their William Hill Scottish Cup semi-final at Hampden Park on Saturday.
The Jambos have won only one game in their last four with boss Craig Levein coming in for criticism from some supporters after last week's derby defeat by Hibernian at Tynecastle, but they remain favourites against the Championship outfit.
The 34-year-old former Wolves and Ipswich defender, who, in his first spell at Hearts was an unused substitute in the 2006 final when the Gorgie men beat Gretna on penalties at Hampden, is aware of the potential for a cup upset.
Berra said: "Everyone naturally will see us as favourites because we are in the top league.
"But these games are always difficult. Even in the previous rounds, when we played against Partick Thistle, we found it difficult ourselves.
"So they are no mugs.
"Our form has been a bit up and down so we know that on the day we need to perform and if not it is going to be a tough day.
"On their day Inverness, who have been in relatively good form, play good football and we will respect them and we know how tough it is going to be.
"It is a massive game. All the boys are looking forward to it.
"In Scotland and England over the years there has always been upsets.
"We know how hard it will be and it will be about who turns up on the day and takes their chances."
Berra, capped 41 times for Scotland, is keen to consign last week's 2-1 defeat by the Easter Road side to history.
"It was obviously disappointing to lose," he said.
"On another day we could have scored more goals. It wasn't to be and you have to take it on the chin.
"We have to play them in a couple of weeks but you have to move on.
"Football moves fast, it is a week-to-week business and we have to put that to bed and luckily enough we have a massive game to bounce back on."
That defeat saw some Hearts supporters round on Levein but Berra insists that is simply "part and parcel" of the game.
He said: "That's football. The gaffer is used to it.
"When you are in the firing line, no matter what club you play for, if you don't get results there is going to be a section of fans who are not happy.
"You can go to any ground in the country including England and that would be the same.
"You have to take it in the chin and move on."