Gareth Southgate resting England's best is a gamble that will pay off only with a win vs. Colombia

KALININGRAD, Russia -- So now the pressure begins to build for England and Gareth Southgate.

After failing to top Group G following defeat Thursday in Kaliningrad against Belgium, a round-of-16 clash with Colombia in Moscow awaits on Tuesday, and it is one Southgate has billed as England's "biggest game in a decade."

It could have been Japan in Rostov on Monday, but Adnan Januzaj's 51st-minute goal settled this game in the Red Devils' favour. Both Southgate and Belgium coach Roberto Martinez made wholesale changes, having already qualified for the next round, and neither seemed particularly concerned about winning.

There are rewards and downsides for finishing first or second. Belgium have secured an arguably easier round-of-16 tie against Japan, but after that, Brazil potentially lie in wait in the quarterfinals. If England overcome Colombia, they will take on either Sweden or Switzerland for a place in the World Cup semifinals for the first time since 1990, so take your pick from the respective routes to the final.

But by making the changes to his team and resting the likes of Harry Kane, Jesse Lingard and Raheem Sterling, Southgate has made his bed and he now has to lie in it. Perhaps it is a case of damned if he did and damned if he didn't in terms of the changes to his team, but by failing to avoid defeat, have England lost crucial momentum, and have they set themselves up for a fall?

Tuesday, in the Spartak Stadium, will tell us all, but the England manager was unrepentant about his decisions after this game, insisting that it was sensible, rather than foolish, to keep his big guns off the pitch.

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"The knockout game is the biggest game for a decade, so we had to make sure our key players were preserved," Southgate said. "If someone had raked Harry [Kane]'s ankle if we'd put him on for 10 minutes, that would have been ridiculous. The knockout game is the important one.

"When you're a leader and a manager, you have to make decisions which are right for your group and the primary objective. Sometimes those decisions will be criticised and I understand that.

"We could have played [the key players] again tonight but, this afternoon, you already saw Colombia lose a key player, Japan lose a key player, Senegal had they gone through would have lost a key player. Those were risks we didn't need to take."

Perhaps Southgate and England will be rewarded with a group of fresh players, eager to go again against Colombia, who have been pushed to the wire in three Group H games and face an anxious wait over the fitness of talisman James Rodriguez, who limped off during the first half of Thursday's crucial 1-0 win against Senegal. Players need to have energy in the tank to win a World Cup, and Southgate is banking on his squad being fitter and fresher after being rested in Kaliningrad.

"You have to think physically, medically, tactically for the benefit of the group," he said. "We have 20 outfield players who have played in the World Cup and that's extremely beneficial for the feeling in our camp.

"I'm entirely comfortable with the decision. Sometimes you have to make decisions for the bigger picture. That's what I did tonight."

England have never lost to Colombia in five previous meetings, winning their most recent World Cup encounter at France 98, when David Beckham scored a memorable free kick in Lens. They sit 16th in the FIFA world rankings, just four places below England, and are a clear threat to their progress, but Southgate insists there was no easy option ahead of his team.

"It will be difficult," he said. "I thought Senegal would also be a very tough game in a different way. All that group was up in the air.

"Colombia have got some outstanding individuals, but I believe it's a game we can win. We feel we're a team who are improving. We have levels still to reach and work to do, but that's nothing we didn't already know.

"That's not a bad thing. If we'd won again tonight, the reality of where we are might not have been in people's mind. We know where we are.

"We know how immaculate we have to be to win matches against the best teams.

"Whatever happens next week, the selection was the right decision as far as I'm concerned. People will say it is only the right decision if we win, but we're potentially going into a match with extra time having risked players we didn't need to risk."

Southgate has gambled, and time will tell if it paid off.