(Adds quote, Fenerbahce response)
ISTANBUL, Aug 9 (Reuters) - Former Turkey coach Ersun Yanal resigned as coach of Turkish champions Fenerbahce on Saturday, leaving the club's preparations for the season in disarray three weeks before the league kicks off.
Yanal took charge of the Istanbul club in June last year and led them to their 19th league title last season.
"As a coach who made my team the champions in his first season, it is impossible for me to continue in the current conditions," he wrote in a resignation letter reported by broadcaster NTV on its website.
"Principles will always be indispensable for success and more important than the money we earn," Yanal added.
He had replaced Aykut Kocaman at a time of upheaval for Fenerbahce, who were banned from European competition for two seasons over their involvement in a domestic match-fixing scandal.
Yanal, who was national team coach between 2005 and 2007, had recently fallen out with club chairman Aziz Yildirim, according to media reports.
In a terse statement on their official website (www.fenerbahce.org), Fenerbahce said they had received Yanal's resignation letter on Saturday evening and indicated they had accepted it.
"We on the management board of Fenerbahce sports club thank Mr Ersun Yanal for his contributions to our club until today and wish him success in his future life," it said. (Writing by Daren Butler; Editing by Rex Gowar)