Juanfran joined Atletico from Osasuna in 2010 and his deal expires in June.
Although Sime Vrsaljko's arrival this season means a first-team place is no longer guaranteed, Juanfran is keen to remain with Diego Simeone's squad.
"I'm going to continue at Atletico," he said after the Sporting win.
"All that is missing is the signature, which is going to be done shortly."
"Winning a derby is very special game," added Juanfran.
"We are going to put our hearts into it and play to win, to distance ourselves even more from third place and to be expectant of what Barcelona are doing.
"If we lose, we keep second. We're winners. "