Hosts Russia or Croatia, who meet later on Saturday and are lower ranked than Southgate's side, are all that stands between England and a first World Cup final since they won the tournament on home soil in 1966.
Croatiacoach Zlatko Dalic also makes one change to his team following the win on penalties against Denmark in the round of 16.
The arrival of the host nation for the final World Cup match at the Fisht Stadium meant by far the most vibrant atmosphere yet at this Black Sea beach resort.
The hosts went ahead thanks to a bolt from the blue just after the half-hour mark. Russia'sDenis Cheryshev started the scoring in the second match of the day with a goal that is a shoo-in for any list of great World Cup knockout goals.
His first, in the opening 5-0 win over Saudi Arabia would most likely finish third on this list for its simpler finish, but Cheryshev had the most lovely of first touches, delicately flicking it up over the sliding defender, taking another touch before firing it home and doubling Russia's lead.
It did not take too long for Croatia to get back on track as Mandzukic turned provider for the equaliser, charging down the left and pulling back for an Andrej Kramaric free header from seven yards.
The Croatian players were quick to take back the initiative in the game and by the middle of the first half they registered the ball possession at nearly 70% against Russia's slim 30%.
The game went to extra-time with Subasic staying on the pitch despite appearing to injure his hamstring late on in normal time.
Ivan Perisic hit the post for Croatia in a second half they controlled but they had to wait until the 101st minute to go in front, defender Vida heading in a corner before removing his shirt as he ran away in celebration.
But against Croatia their unbelievable run ended at the quarter-final stage despite taking the lead after 30 minutes.
But Pivaric was whistled for handling the ball at the corner of the box, and Dzagoev's cross was flicked inside the back post by Fernandes to level the game in the 115th minute.
His shoot-out miss proved pivotal, however, especially after Smolov's weak attempt at a chipped penalty was saved by Subasic.
Croatia's Dejan Lovren and Russia's Fyodor Smolov look up at the ball.
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Robin Haase, Netherlands, 6-3, 6-4, 7-5. "I was thinking about every single point when I was serving for the match", Kerber said. Eugenie Bouchard of Canada, who lost to Kvitova in the 2014 Wimbledon final, lost to 17th-seeded Ashleigh Barty 6-4, 7-5.
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Mourinho said he believed England have a "golden chance" to reach the World Cup final for the first time in more than 50 years. Romelu Lukaku and Eden Hazard have been key players for Belgium . "We don't get all the information from the French team".
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But Gareth Southgate's side also did well to respond after conceding an equaliser so late, and obviously recovering from that. It was his solitary goal against Switzerland that ensured Sweden enter the quarterfinal stage and set up a date with England.
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He added that he did not see consistency in Croatia's game as they "looked good for three games but played worse against Denmark". That Croatia side hammered Germany 3-0 to reach the semis in France, and Dalic is looking for a similar result on Saturday.