Given Croatia had extra time and penalties to recover from, England should come into the game fresher and they also have the edge in previous meetings, winning four of the seven encounters, including a 5-1 victory in their most recent match - a World Cup qualifier in 2009.
Kieran Trippier opened the scoring with a brilliant free-kick into the top-corner inside five minutes - and then England dominated in the first half, with Harry Kane having the pick of the chances: one on one with Danijel Subašić, the Spurs striker aimed his initial shot at the keeper and then hit the post with the follow-up.
Croatia's Mario Mandzukic went down hurt in added time after colliding with England goalkeeper Jordan Pickford, who blocked his shot.
But there were stunned reactions as Croatia scored the equaliser through Ivan Perisic. When Southgate finally made the change late in the second half, it was to replace Henderson with Eric Dier rather than support him.
Speaking to the presenter Marc Pougatch, Keane says: "Before the game, we were talking about England and the final, France". Our supporters, our country has had a long time of suffering in terms of football.
"Obviously it's been good to get to this stage and we've done everyone proud but we wanted to go on and win it. but we've fallen a bit short".
"I'm not surprised that Croatia have identified Raheem as a key player", said the 47-year-old Southgate.
Excitement has reached fever-pitch levels back in England, with Gareth Southgate's young team making it to the last four of a major tournament for the first time since Euro '96, and for the first time at a World Cup since Italy in 1990.
Mario Mandzukic's extra-time goal saw off England in heart-breaking fashion.
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Perisic came close again and Mandzukic had a shot saved by Pickford as Croatia pressed for the victor but it wasn't to come and the game headed into extra-time.
What is not in doubt is their quality.
England's lack of a genuine creative midfielder is not a new problem and Southgate has done well to devise a system that can compensate for that weakness.
Croatia relied on penalty shootouts to advance in their round of 16 tie with Denmark, as well as their quarter-final date with Russian Federation, which suggests that they have the collective concentration to last 120 minutes, as well as the cool-headedness to maintain composure during penalties.
He said: "They were the better team, that's all that happened".
Alright lads, strap into your VW Polos, drive down to the local pisser, order a round of Carlsberg Special Brews and locate the least moist pub booth you can: it's the World Cup semi-final showdown between England and Croatia.
England initially regrouped well in extra time with Marcus Rashford introducing some pace and Croatia were grateful for Vrsaljko's goalline clearance of a John Stones header.
The goal was followed by a series of chances for England as Croatia struggled with the pace of the Three Lions' attack. You know how hard it is to get to these big finals, or even get to a World Cup.