The 24-year-old had a huge part to play in the opening goal when his strike took a deflection off Jack Robinson to wrong foot Alex Smithies and give Fulham the lead before the break.
Stefan Johansen got his second goal in two games after Rui Fonte teed him up on the edge of the box, with QPR affording him too much space and time, allowing him to rifle the ball into the bottom corner.
Conor Washington got what proved to be a consolation goal in the 92nd minute - another goal that Fulham conceded after going ahead, something that Fredericks has said is becoming an annoying habit.
He said: "It's becoming a bit of an annoying habit, conceding late goals, but we rode it out against QPR and it gives us confidence that we can survive when the tide is against us.
"We should've won the Middlesbrough game too, but we'll take what we've got - seven points in six/seven days isn't too bad and we need to keep up this form and keep climbing now.
"We weren't too fussed about the performance, we weren't the best in the second half but the important thing is the three points and climbing up the table."