Atletico Madrid coach Diego Simeone said the team with the best "emotional balance" will win La Liga after watching his side lose 2-1 away at Athletic Bilbao to leave the title race on a knife edge.
Wins over Eibar and Huesca had corrected Atletico's title course but Simeone's side were outplayed by Athletic for most of the game and can have few complaints abut the result.
Alex Berenguer's diving header put the hosts ahead before Atletico defender Stefan Savic levelled with a header from a corner. The third headed goal of the game settled the match as Inigo Martinez thumped home for Athletic.
"People ask me what the most important factor will be and it's obvious to me that it will be the mental factor," Simeone told reporters after a second defeat in five league games.
"We did not play the way we wanted to in the first half, it was totally different in the second, and the team that manages that emotional balance the best will have the best chance of winning the title."
Atletico were 10 points clear at the top in January with a game in hand but a dismal run of form has seen their lead cut to two points and Barcelona will knock them off the summit if they beat Granada on Thursday.
Real Madrid are also only two points behind Atletico while Sevilla are three back in a thrilling four-way tilt.
Simeone did not dwell on how his side had thrown away their sizeable advantage and emphasised that they would claim the league title if they won their remaining five games.
They visit Elche next before a crunch visit to Barca, then host Real Sociedad and Osasuna before a trip to Real Valladolid.
"Real and Barca are used to winning the title. We had a big lead this year but we knew Real and Barca were not going to surrender. Now Sevilla are playing very well and we have a very exciting situation," said Simeone.
"We still depend on ourselves and with five games to go that's crucial. It will all come down to how mentally strong we are and how determined we are in those five games."
