Last updated on .From the section European Football

Ajax celebrated a fourth successive Dutch league title under Frank De Boer's management despite being held to a 1-1 draw at struggling Heracles.

The draw left the Amsterdam club four points clear of nearest rivals Feyenoord with one round of Eredivisie fixtures remaining.

"We've beaten almost all our direct competitors. The title is justified," said De Boer.

Frank De Boer The former Netherlands international and assistant coach was named Ajax boss in 2010 after the exit of Martin Jol and signed a new four-year contract last summer

He is the first manager in the Eredivisie to win four straight titles.

Lasse Schone fired Ajax into an early lead before former Red Bull Salzburg midfielder Simon Cziommer equalised.

"I am proud," added De Boer. "It was not the prettiest game, but eventually we dragged in the title."

It is the 33rd time Ajax have won the Dutch title.

A league double over Feyenoord played a big part in Ajax's latest league triumph, while they also took four points against third-placed FC Twente and responded to September's 4-0 loss to PSV Eindhoven by winning the return fixture.

"If we see that after the winter break we beat Feyenoord, Twente and PSV and drew with Vitesse, then we are worthy champions," added De Boer.

"Over the whole season we've been the best."

Last week Ajax suffered a humiliating 5-1 defeat against PEC Zwolle in the Dutch Cup final.