Another long-serving manager of a Peterborough United League One rival departs and what Posh need to do to jump two places on Tuesday
Robinson was coming up to the fifth anniversary of his appointment at Oxford, but a run of one point in the last eight League One matches prompted his departure 24 hours after a 3-0 home defeat at the hands of Bristol Rovers.
Robinson, a big foe of Posh when he was managing MK Dons, had been the third longest-serving manager in the third tier after Gareth Ainsworth at Wycombe Wanderers and John Coleman at Accrington Stanley. Ainsworth ended his decade in charge of the Chairboys to take up a managerial post in the Championship at QPR at the end of last week.
Coleman took charge for the second time at Stanley in September, 2014. The next longest-serving League One managers are Mark Bonner (Cambridge), Ian Evatt (Bolton) and Steve Cotterill (Shrewsbury) who were all appointed in 2020.
Oxford are 17th in League One, just five points above the relegation zone. They visit the Weston Homes Stadium on April 1 and former Posh boss Grant McCann is bound to be linked with the Oxford job.
Coaches Craig Short, Leon Blackmore-Such and Wayne Brown have been put in temporary charge.
An Oxford club statement said: "The board would like to thank Karl for his hard work and efforts in the five years since he joined, but recent results and performances mean that a change is needed."
Oxford have won three of their past 16 league games under Robinson. He took Oxford to the League One play-offs in successive seasons, losing in the final at Wembley to Wycombe in 2020 and at the semi-final stage to Blackpool the following year.
Wycombe lost their first match without Ainsworth, 2-0 at play-off rivals Shrewsbury on Saturday. Posh will jump above both clubs into seventh if they beat Charlton Athletic at London Road on Tuesday.