Rodrigo De Paul's superb volley earned Atletico Madrid a 1-0 win over Celta Vigo on Sunday to virtually guarantee Champions League football next season.
Diego Simeone's side, fourth, move eight points clear of fifth-place Athletic Bilbao with just three games remaining.
After the Copa del Rey winners drew against Osasuna on Satuday, Atletico left it late but were able to take advantage to move further clear.
De Paul struck after 84 minutes to delight fans at the Metropolitano stadium just as it seemed all the hosts' pressure would come to nothing.
"When I'm on the edge of the box I've got confidence and I know I have to finish the move so there's no counter-attack, I knew I'd hit it if it fell to me," De Paul told DAZN.
"We need two more points to make (Champions League qualification) mathematic."
Atletico Madrid dominated from the start but found it hard to beat former Crystal Palace goalkeeper Vicente Guaita.
The Spaniard saved well from Angel Correa and Rodrigo Riquelme in the early stages and then stopped Marcos Llorente's tame effort before half-time.
Atletico's Jan Oblak did well to deny Iago Aspas early in the second half when Celta carved out a rare chance of their own.
Guaita saved a Memphis Depay effort at his near post before brilliantly tipping Pablo Barrio's acrobatic shot on to the crossbar among a string of fine stops.
The goalkeeper thwarted De Paul moments before Atletico took the lead, when the Argentine took a touch to control a clearance on the edge of the box and slashed a volley across goal and into the top corner.
Defeat leaves Celta 16th, five points above the drop zone after Cadiz, 18th, scraped a narrow 1-0 win over Getafe earlier Sunday.
"We had so little to go to get a point... each point is important because we're in a situation where the sooner we can be mathematically safe, the better," said Guaita.
Granada, 19th, were relegated to join Almeria in the second tier next season on Saturday before kicking a ball in their 4-0 home defeat by champions Real Madrid.
Barcelona, third, can overtake second place Girona with a win against Real Sociedad on Monday.
The Basque side, sixth, are battling to secure Europa League football next season. Real Betis, seventh, host Almeria later Sunday.
