Karachi, Sep 21 : The touring England side has suffered a setback, with assistant coach Richard Dawson suffering a groin injury and being ruled out of the seven-match T20I series here and the ICC T20 World Cup in Australia next month. Dawson will fly back to England to begin his recovery. Dawson had to be carried off the pitch at the National Stadium in Karachi -- where the first T20I was played on Tuesday evening -- after pulling up during a training session earlier and had to return to the team hotel in a wheelchair, said a report in ESPNcricinfo. "After being assessed in Karachi, he will be unable to continue during this tour of Pakistan and will fly home to the UK on Wednesday," the ECB said in a statement. Dawson was one of white-ball head coach Matthew Mott's three assistants on the historic Pakistan tour along with Carl Hopkinson and David Saker, with Australian Michael Hussey set to join the staff in Australia ahead of the ICC T20 World Cup next month. A replacement coach for the World Cup will be announced at a later stage, said the ECB. The report said one of the Test assistant coaches under Brendon McCullum could be drafted into the white-ball support staff following the injury to Dawson. England began their sub-continent campaign on a winning note on Tuesday with their opening batter Alex Hales blasting a half-century as the visitors defeated Pakistan by six wickets with four balls to spare to take a 1-0 lead in the seven-match T20I series. With Pakistan and England priming for the ICC T20 World Cup in Australia, Hales' stunning return to the international game -- aided by seven boundaries -- and Harry Brook's hitting at the back end, helped England overhaul Pakistan's 158/7 in 19.2 overs. /IANS