2018 Fifa World Cup last 16 Venue: Russia Dates: 30 June - 3 July Coverage: Watch live on BBC TV, Red Button and iPlayer, BBC Sport website and app; listen on Radio 5 live; follow text updates online

There is plenty to be positive about for England right now, not just because of what we have seen from Gareth Southgate's side but also from everyone else at this World Cup so far.

With 16 teams left, and the knockout stage about to begin, the tournament looks very open to me.

Up to now there has not been an outstanding side in Russia - which is another reason to feel encouraged about the Three Lions' prospects.

Croatia, Uruguay and Belgium all won three games out of three in the group stage, but I have not seen anyone that has made me think, "wow, this is the team to beat".

Even so, I have not changed my mind about how far I think England can go in Russia - or what would make this tournament a successful one for us.

Before the World Cup started, I saw the quarter-finals as a realistic aim, and a decent performance by a young team too, and us being in what some people perceive to be the easier half of the draw does not make a difference to either.

I also don't think we can start picking and plotting our route to the final and say we only have to beat Sweden or Switzerland in the quarter-finals and we are in the last four.

With our record at major tournaments, how on earth can we be so arrogant to look ahead like that, or think we will roll anyone over?

England have won two knockout games at World Cups since 1990 - against Denmark in 2002 and Ecuador in 2006 - so, before we get carried away, let's deal with Colombia first.

Get back to high-pressing style

Player for player England are better than Colombia - Jenas

I don't feel as if we have much to fear from Colombia but I do think we will have to play our best football to get past them.

By that I mean return to the high-tempo pressing style that we played against Tunisia and Panama. In fact, we need to step up, because Colombia are much better than both of those teams.

I am looking forward to seeing how Harry Kane gets on against his Tottenham team-mate Davinson Sanchez, and that is one of the personal battles that might prove to be pivotal in deciding the end result.

Friendships go out of the window in situations like that - no matter how much you like someone, you just want to beat them.

That was definitely the case with me when I came up against my Blackburn team-mate Colin Hendry when England played Scotland at Euro '96.

There was plenty of stick between us beforehand, but when the game starts you are there to do a job and if Harry is anything like me, he will just want to go out and kick his backside.

Harry will know all about Sanchez's strengths and weaknesses, and be able to use that to his advantage.

My take on Sanchez is he is quick and strong but not so good on the ball. That is why pressing him is a good idea, but Harry will know all about that.

England have risked losing their rhythm

I am expecting England to revert to the same kind of line-up that faced Tunisia and Panama, with the only issue being whether Dele Alli is fit to return and replace Ruben Loftus-Cheek.

My only worry on the back of all the changes we made against Belgium is that we have lost some of the momentum we built up while winning our first two games in Group G.

As I said beforehand, bringing in one or two players would have been fine. Anything more - like the eight changes Gareth made - risks disrupting the rhythm this team had been building up.

Things were a bit different in the three major finals I played at with England, because on each occasion there was something riding on our final group game.

But, if things had been different, and we could have had a rest after, say, we beat the Netherlands 4-1 at Euro '96, then I would not have wanted one.

I don't think our manager Terry Venables would have made so many changes either.

Nobody took their chance to impress

It did not really work out for us against Belgium, who made nine changes themselves. All we really found out was that they have got a better back-up team than we have.

Things might have been different if the England players who came in had done well, but they did not take their opportunity to press their claim for a starting place.

That includes Marcus Rashford, who had our one clear chance when he was put through on goal.

It was a brilliant position to be in as a forward, because he was so central. Marcus could have gone to the left or the right with his shot, or he could have sold the goalkeeper a dummy and gone round him.

What you cannot do is miss the target the way he did. That was his big chance, especially because I felt like if there was one place up for grabs against Colombia then it was in that position behind Harry Kane.

If he had put that away, Rashford might have got the nod over Raheem Sterling, who has not repeated his goalscoring form for Manchester City when he has played for England.

Now I am pretty sure Gareth will stick with Sterling, and Tuesday would be a good time for him to end his international goal drought, which has lasted 22 games since 2015.

The England player who needs a goal the most is definitely him.

Alan Shearer was speaking to BBC Sport's Chris Bevan in Moscow.