Paul Lambert has stood down as manager of Livingston after a 1-0 defeat at home to Dunfermline left his side six points adrift at the foot of the SPL.
The former Celtic and Borussia Dortmund midfielder had hinted that only a victory would persuade him to stay.
"As from now, I am no longer Livingston manager," he told a news conference.
"My assistant, Norrie McWhirter, and I have given it our best, but it's about time for someone else to come in and see if they get the breaks we didn't."
Lambert, who was Livi's third manager in 18 months, had taken over in the summer after former Rangers defender Richard Gough had ended his short spell at Almondvale by avoiding relegation on the final day of the season.
The 37-year-old, like his fellow former Scotland international, was in his first managerial job but had prepared for the role by taking time off from Celtic to take coaching badges in Germany.
But, with his side sitting bottom of the Scottish Premier League, Lambert rejected pleas by owner Pearse Flynn and chief executive Vivien Kyles to stay.
"The two people who brought me here were terrific to work for and I was grateful of the chance to get into management," he said.
"The players have given it everything they had, but it remains private why I have gone.
"I will take a break and look forward for the first time in my life to being out of football for a little while, but I am not disillusioned with football."
Lambert had taken charge with the intention of concentrating on management but re-registered as a player in August after a poor start to the season.
"I think we lost every game I played in," he joked.
"But Livingston have got every chance of staying in the league is someone else comes in and gets the breaks."
Lambert's side had suffered a 7-0 midweek humiliation at the hands of Hibernian, after which Flynn held a lengthy post-match meeting with the team boss and the players.
However, Lambert stressed that there was "a very good chance" that he would have remained in charge had they beaten Dunfermline.
Kyles said: "We are very disappointed with the position that we are in, but it's a results business.
"The guys have given everything and have lost games that they should have won given the quality of their play.
"So it is with regret that we accept Paul's resignation.
"It's Paul's decision that he is not the person to take us up to the end of the season."