A key player in the Atletico Madrid team that won a La Liga and King's Cup double in 1996 and now the club's inspirational coach, Diego Simeone has led his unfancied team to the brink of an even greater achievement.
Atletico's stunning 1-0 home win over Barcelona in Wednesday's Champions League quarter-final, second leg, which sealed a 2-1 aggregate success against their La Liga rivals, secured their place in the last four of Europe's elite club competition for the first time in 40 years.
In La Liga, they are a point clear of Barca with six games left and three ahead of neighbours Real Madrid, closing in on what would be an incredible title for a club whose long-suffering fans have grown used to the dominance of Spain's vastly wealthier big two.
Simeone was an intense, never-say-die character as a player for Argentina and various clubs in Spain and Italy and remains so as a coach. It appears to have rubbed off on his players.
Their commitment and sheer guts in holding out against waves of Barca attacks near the end of Wednesday's game at the Calderon was typical of a season which has seen them humble some of Europe's biggest clubs.
They thumped seven-times winners AC Milan 5-1 on aggregate in the Champions League last 16, beat Real 1-0 at the Bernabeu in September in La Liga and have drawn five and won one of six meetings with Barca this term in all competitions.
From top scorer Diego Costa, to playmaker Koke, through centre backs Miranda and Diego Godin to goalkeeper Thibaut Courtois, Simeone has got the very best out of players who had achieved little before he took the helm at the end of 2011.
Atletico's adventures this term may still have an unhappy ending but few of the supporters who have experienced the electric atmosphere at the Calderon in recent months will forget the Simeone effect in a hurry.
The 43-year-old hardly sat down on Wednesday, prowling his technical area, bellowing tactical advice, encouraging his players and whipping up the adoring fans chanting his nickname "Cholo".
Atletico will find out which of Real, Chelsea and holders Bayern Munich they will play in this month's Champions League semi-finals in Friday's draw and play at Getafe in La Liga on Sunday.
"We will maintain our humility," Simeone told a news conference after the Barca game.
"The other teams (in the Champions League semi-finals) have been there more often in the past few years but we are confident in our work and the opportunity we have.
"Our hope is to finish this competition being competitive, as we were when we set out.
"We will continue to work calmly because nothing has been won yet. We got through one tie and there is a long way to go."
Atletico won the Europa League, Europe's second-tier club competition, in 2010 and 2012 but have never claimed the top continental prize.
They are the clear underdogs alongside three teams with hugely superior resources but know the pressure will again be on their opponents in the next round.
And as they have proved time and again this season, with "Cholo" inspiring them, anything is possible.