Underdogs in a group containing two former champions, Belgium beat Spain 2-1 to put themselves in pole position to reach the final.
As was the case in Spain's opening goalless draw against Italy, sweeper José Ramón Alexanko stayed deep, allowing Belgium the room they needed to threaten on the counterattack. Ahead through Erik Gerets, Guy Thys' side were pegged back by Quini before half-time but secured the victory through Julien Cools' effort midway through the second half.
That slender lead was one Belgium never surrendered, though it could have been far more comfortable if they had been more clinical in the opening period, François Van Der Elst and Erwin Vandenbergh particularly guilty of spurning opportunities. Gerets, one of the great right-backs, showed his forward colleagues how it was done on 17 minutes, however, racing upfield and scoring with a low finish.
Spain drew level nine minutes before the interval, Quini heading Juanito's lofted free-kick across goal and past Jean-Marie Pfaff, but the departure of Juan Manuel Asensi proved a disruption to the Roja's midfield rhythm from which they never recovered.
Belgium remained in charge and duly went in front once more with 25 minutes left. Jan Ceulemans, in the thick of things as always, broke away on the right and delivered a cross which was deflected en route to the penalty area. Goalkeeper Luis Arconada hesitated under pressure from Van der Elst and Cools was on hand to put the ball into the roof of the net.
Unless Italy won by two goals that evening, the group outsiders would need only a draw against the Azzurri to reach the showpiece.