Gary Cahill believes England's defeat against Belgium will act as a reminder of the challenges ahead at the World Cup.
England progressed to the knockout stages as runners-up in Group G following the 1-0 loss in Kaliningrad, where manager Gareth Southgate had made eight changes to his starting XI.
Chelsea defender Cahill accepts England have been given plenty to think about, but insists they can still take momentum from previous pool victories against Tunisia and Panama into their last-16 showdown with Colombia in Moscow on Tuesday night.
"The Belgium game was a reminder to us of the standard of teams we are coming up against from now on," Cahill said.
"No disrespect to Panama, but that was a different test. The way they (Belgium) moved positions and kept the ball - it was a good benchmark for what is to come.
"We made eight changes - nine if you include the substitution at half-time. Things were always going to be a little bit disjointed.
"The first half was good, the second was a bit stretched, but nevertheless we just move on to the knock-out phase. Now this is the business end."
Cahill sees no reason the loss against Belgium, in which England captain Harry Kane was left on the bench, should put the Three Lions off course.
"It doesn't derail us," he said. "It won't affect our momentum. It was disappointing to lose the game, but we have lost nothing.
"This is an opportunity to go through to the next round. We are going into it with a lot of positivity. We have earned the right to play in this game."
Cahill added: "Colombia are a very good side, but it's all ifs and buts isn't it? It's going to be difficult, but they will all be.
"It's like any competition: The longer you stay in it, the less likely you're going to dodge any big teams.
"This is the business end. The next match is the important one. We look no further than that."