The Cottagers came from 2-0 down to lead 3-2 in Saturday's Barclays Premier League game at the Emirates Stadium, although the game ended in a 3-3 draw to leave them ninth in the table.
Sweden star Kacaniklic scored Fulham's equaliser after coming off the bench for the injured Kieran Richardson and said: "I think this performance bodes well for the future. We came to a difficult ground against a top team, but played our way and really made it our game."
The 21-year-old admitted he was surprised to score with his head, adding on his club's official website: "I can't remember the last time I scored a header.
"It had been a while. I like to think I took the chance well, but the build up play and cross was absolutely fantastic. It was a really great move.
"It doesn't matter who scored the goal but, of course, it was nice to play my part."