AMSTERDAM - AZ Alkmaar clinched the Dutch league championship for the second time on Sunday with three games to spare. Louis van Gaal's side were crowned champions for the first time since 1981 after Ajax Amsterdam failed to beat PSV Eindhoven. AZ, who have secured a place in next season's Champions League group stage, could have clinched the title on Saturday but lost 2-1 at home to Vitesse Arnhem. They are 11 points clear of second-placed Twente Enschede, who also lost on Saturday, 1-0 at Feyenoord. Ajax, who lost 6-2 at PSV on Sunday, remain third a point further back. It is the sixth league title for Van Gaal after he steered Ajax to success in 1994, 1995 and 1996 and led Barcelona to Primera Liga glory in 1998 and 1999. The Dutchman was also technical director when Ajax won the league in 2004. "This championship is my true masterpiece" Van Gaal was quoted as saying in Dutch weekly Voetbal International. "The possibilities at Ajax and Barcelona are much bigger. They can buy big players and besides that they can pick players from their own youth department." Van Gaal uncovered a key player in prolific Moroccan striker Mounir El Hamdaoui, who scored his 22nd league goal on Saturday. His tally is more than a third of the team's 62 goals so far. AZ's triumph should make up for their near miss two years ago when they lost the title on the final day of the season but Van Gaal said: "This title doesn't take away the bad taste of 2007 because we should have won the double that year." Van Gaal was disappointed his team underperformed on Saturday, saying: "We were not able to handle the pressure of a championship match. "Too many players performed less well than they are used to. It is a pity we failed to be satisfactory to the expectations of our crowd, who were ready for the title."