Rayo travel to Paco's old club Real Zaragoza on Sunday, having gone into the weekend seven points off a Europa League slot after three games without a win.
But Paco is well aware of the threat posed by the hosts, who finally ended their dismal run of 14 La Liga games without a win when they beat bottom club Real Mallorca last Saturday.
Paco said: "We are aiming to achieve qualification for Europe, which will be historic for the club, and we must do everything possible not to let it slip through our hands.
"Zaragoza had gone so long without winning, but they have a good team and they are very dangerous because of the position they are in."
Zaragoza's priceless 3-2 win over Mallorca dragged them to within one point of safety and midfielder Ruben Rochina believes his side's home form during the run-in will prove crucial to their survival prospects.
Rochina said: "We have a lot of games at home in the run-in and it is all about getting good results with the support of the fans.
"The win last week was good for team morale, but the most important thing is to focus on Sunday because the work is not yet finished.
"We need to go out and give everything for the club and we need the fans to be behind us all the way."