text: Liverpool-bound striker Dominic Solanke picked up Lewis Cook's pass to score the winner shortly after the interval.
  England played the last 17 minutes with 10 men after Josh Onomah was sent off.
  Freddie Woodman was required to make key saves late on as Paul Simpson's side held on to reach the semi-finals for the first time in 24 years.
  Italy beat Zambia 3-2 after extra time and will face England in Jeonju on Thursday.
  The other semi-final sees Uruguay take on Venezuela.
  After a goalless first half, Bournemouth midfielder Cook split the Mexico defence with an exquisite ball from deep that Solanke, who will join Liverpool from Chelsea next month, ran on to before firing past Abraham Romero.
  England also saw a goal-bound deflection cleared off the line and Onomah hit the post before the Tottenham midfielder was dismissed in contentious circumstances.
  The 20-year-old appeared to make accidental contact with Juan Aguayo as he ran past his marker but was shown a second yellow card that rules him out of the Italy game.
  England Under-20s last reached the final four of this competition in 1993, when a squad featuring Nicky Butt and Nick Barmby lost to Ghana in the semis before beating Australia to finish in third place.
  BBC sports editor Dan Roan
  These are encouraging times for English youth football. Last season, the Under-21s won the Toulon tournament for the first time in 22 years. Last month the Under-17s reached the final of the European Championships.
  The U20s have now done something no England team has managed since 1993.
  In fact, England failed to qualify for five of the last 11 Under-20 World Cups, and did not win a game in the other six.
  The FA believes this current success is testament to the continuity and technical support representative teams receive at the National Football Centre at St George's Park, and improved trust with clubs over the release of young players.
  But with the top clubs awash with TV money and increasingly able to buy proven foreign talent, the concern will be that the path to first-team football for home-grown youngsters is harder than ever.
target: England will face Italy in the semi-finals of the Under-20 World Cup in South Korea after a 1-0 victory over Mexico in Cheonan.