Mitrovic had been struggling for game time at Newcastle United in the first half of the season, leading to him dropping down a league on loan.
His 12 goals in 17 Championship starts were instrumental in helping Fulham to a 23-match unbeaten run which saw them just miss out on automatic promotion to Cardiff City before they sealed a spot in the Premier League with a Championship play-off final win over Aston Villa.
The 23-year-old has since staked his claim for a starting spot in the national team this summer, having scored a hat-trick against Boliva in Serbia's final friendly ahead of the World Cup.
"I will try to make them proud. I just wanted to play football and enjoy on the pitch," Mitrovic told Goal. "I came into a team that played football that is really good for me and my abilities. I had a lot of balls and crosses. If the team plays well and gives me the ball then the goals will come.
"So credit to my team-mates, staff and club. They gave me great support from the first minute I came here. They trusted me and I feel like I've been here for a few years, not a few months. It is a big thing for me, my family, the country and all people in Serbia.
"I tried to give my best, play the best I can and do my job. I think that the main target is to try and pass our group, then after it is just knockout football and anything can happen, but we aim to pass our group."
Mitrovic has yet to have confirmation on whether he will play for Newcastle or the newly promoted Fulham next season.
Serbia begin their World Cup campaign against Costa Rica on Sunday before facing Switzerland and then concluding the group stage with a game against Brazil.