Wow! I honestly had no idea. Given how much offense Mitrovic supplies Fulham at such a disproportionate rate to the rest of the club, it makes sense to me that they would concede only 2 goals en route to winning that many games. You basically win 1-0 or nothing in his absence because you're not so likely to get that 2nd goal. So theoretically, you're not gonna see many goals given up and 2 definitely sounds right given 6 wins and a draw. But that's still really damn impressive to win that much without a player who is that important. Given the aggregate and their success without him, Fulham could still conceivably give him the next game off.
Talk about putting yourself in the best possible position
It's a stat I came across by pure accident.
In the 40 league games where Mitrovic did feature, they conceded 46 goals and kept 13 clean sheets , so the improvement is notable. (Brentford, Leeds and West Brom all averaged under 1 goal against per game across the full season).
Naturally, the small sample size limits how much should be read into the numbers. Several teams scored more goals than Fulham despite Mitrovic finishing as the division's top scorer, so without him, likely the club would have missed the playoffs altogether.