The rally world has been shocked by the death of Hyundai driver Breen, who died in a testing crash last week in preparation for the asphalt event.
The fourth round of the world championship has continued albeit in a subdued and sombre manner with all drivers and teams paying tribute to the 33-year-old Irishman.
After careful consideration, which included discussions with Breen's family, surviving co-driver Fulton, and Hyundai Motorsport's crews and team members, the team decided to compete in Croatia but with a reduced two-car line-up driven by full-time drivers Thierry Neuville and Esapekka Lappi.
The cars are carrying a special tribute livery this weekend.
Drivers are both united in their grief but are determined to put on a show to honour Breen.
"Myself, I'm doing not so bad. It's difficult, it's demanding and it's so hard for all of us," said M-Sport's Ott Tanak after Thursday's shakedown.
"It's empty inside and it's eating us alive. It's tough, but I promised to give a smile to Jackie (Craig Breen's mother). We keep going."
Neuville has called for the rally community to stay strong and to compete in the passionate manner Breen displayed during his career.
"We are all very sorry for what happened. It's going to be a tough rally for everybody but as a team and as a rally family we need to be strong and keep going. That is what Craig would have wanted," said Neuville after the shakedown.
He added: "I have many great memories but I think we will remember Craig as somebody who lived his dream 110%, who achieved his goal in life by getting into the WRC and driving the fastest cars in the world.
"He was living it flat out and that is something I think we will always remember. I won't forget his Irish humour and the tea he used to drink, so I will have a lot of memories that I will keep in my mind.
"I know there is a message that we need to transmit now, not only for ourselves but for other people. It is something that I have realised that we have often forgotten over the past years. First of all, we need to have fun, and I think that was one of the strongest messages he was transmitting.
"I had the chance to go to Ireland this week and meet Breen's family to see his mother [Jackie]. I will never forget it as she took my face in her two hands and said "I want to see you smile, Craig was smiling most of the time and you guys need to transmit that message to the people out there."
It is a view echoed by reigning world rally champion Kalle Rovanpera, who said: "It will be really difficult. I am doing just fine at the moment but I think the most important thing is that everybody is here to drive for Craig. That's the goal for the weekend."
Toyota team-mate eight-time world champion Sebastien Ogier added: "I think how we approach this weekend is we go forward because life goes on and we need to go forward. And I think Craig would have loved that the rally went ahead as he loved the sport and would be the first one who would want the show to continue.
"Whoever wins this weekend will have a different taste of victory as it is secondary in this moment."
