"The main thing we have to learn is that it is not over until it's over.
"We never got what we deserved, but that is life, I suppose. I can't explain it."
For QPR, both Mackie and manager Mark Hughes believe the result could be the catalyst for survival.
The win was only their second in 17 games and took them out of the bottom three and two points clear of the relegation zone.
Hughes said: "We might look back at tonight and say this is where it all turned for us."
Liverpool started the game well and could have been 4-0 up inside the opening 12 minutes, as Luis Suarez, Martin Skrtel and Kuyt had chances denied.
Coates fired Liverpool in front nine minutes after the break with a spectacular overhead kick, before Kuyt latched onto the rebound from Paddy Kenny's save off Stewart Downing's shot to double the visitors' lead.
But Derry rose to meet Adel Taarabt's corner to head in his first goal for QPR, before Cisse did the same to level the scores against his old employers.
And Mackie took advantage of some sloppy defending in stoppage time to race onto Luke Young's through-ball and score what could be a crucial goal for both ends of the table.
-AAP