The need for a replacement race for the final Grand Prix of 1984 gave Estoril the opportunity to join the World Championship. Estoril opened in 1972 but it fell into disrepair during the late 1970s. The 1984 Portuguese GP saw the closest-ever finish to the championship, as Niki Lauda edged out McLaren team-mate Alain Prost for the title by half a point. Ayrton Senna won his first Grand Prix at Estoril a year later, delivering a masterly performance in atrocious conditions. Prost had an eventful race weekend here in 1993, securing his fourth world crown and announcing his retirement within a 24-hour period. A new hairpin was built to slow cars at Turn 9 in the aftermath of the 1994 Imola tragedy. The Grand Prix was last held in 1996 as Formula 1 expanded outside Europe.