Another Leicester clean sheet, another Leicester win.

Claudio Ranieri's side moved a step closer to an unlikely Premier League title with Sunday's victory over Southampton and, again, their defence played a huge part in their success.

The Foxes won 1-0 for the fifth time in their last six matches and are now seven points clear of second-placed Tottenham with six games to go.

Only Spurs and Manchester City have scored more goals than Leicester this season but, if they do win the league, it looks like it will be that rock-solid defence which will carry Ranieri's side over the line.

What is their secret? Watford striker Troy Deeney, who has faced them twice this season, tells Match of the Day 2 what it is like trying to break down the Leicester back four.

'Huth is the toughest opponent I have faced this season'

Troy Deeney challenges Robert Huth during Leicester's 1-0 win over Watford at Vicarage Road in March. Deeney scored from the penalty spot against the Foxes at the King Power Stadium in November, but Claudio Ranieri's side won that game too, 2-1

Deeney: "I have played against every Premier League defence this season for Watford, and Leicester's Robert Huth is the toughest opponent I have faced.

"Huth is the sort of centre-half who will let you know he is there, so to speak, with a challenge or two early in the game.

"But when I got my chance, I made sure I let him know I was about too. To be fair, he did not seem to mind.

"Like his team-mate Wes Morgan, who I had many battles with in the Championship earlier in our careers, Huth is old-school - an out-and-out defender who really enjoys the physical side of the game.

"That is normally the side I thrive on too, but I did not have much joy against the German. He is horrible to play against, in the most complimentary way.

"He heads it, he kicks it, and he kicks you - anything - he does not care, as long as the ball does not go in.

Only five Premier League defenders have made more clearances than Huth this season, and he is ranked eighth for number of blocks. "He loves heading the ball," says Deeney. "He loves blocking it, he just wants to defend"

"Huth is not a player who gives you verbals when you are out on the pitch - in both games against him this season, he hardly talked to me.

"But in terms of talking to each other, the whole Leicester defence never stopped for the entire game, including Kasper Schmeichel in goal.

"And if Danny Drinkwater did not hear the right call then he was always going back from midfield and asking what was what too. That is one of the reasons they are so well organised at the back."

'You cannot drag their centre-halves out of position'

Leicester 1-0 Southampton: Claudio Ranieri praises captain Wes Morgan

Deeney: "Part of my job leading the line for Watford is to occupy centre-halves - by that I mean those battles with Huth, say, to try to win headers when the ball is played forward.

"But I also look to bring centre-halves out of position to the flanks and make space for my team-mates in the middle.

"It is difficult to do that against Leicester because their centre-halves, Huth and Wes Morgan, never put themselves in danger of being isolated.

"When Watford had the ball in wide areas they kind of left us to it, and concentrated on dealing with the cross rather than stopping it being put in.

"Huth and Morgan take two positions - one takes the near post and the other takes the middle of the box near the penalty spot as if to say 'go on, cross it, and we will deal with it'."

'Foxes full-backs are defensive-minded too'

Average position of Leicester City's players against Southampton

Deeney: "The other thing that makes it harder to break down Leicester than the other top teams is that both their full-backs are very switched-on defensively.

"Most full-backs in the Premier League bomb on now, and I don't want to be disrespectful to them but it is often a lot easier when you are up against a right winger who has been switched to a right-back.

"It seems to be more about how good they are going forward, and there are not many who are as solid as Danny Simpson and Christian Fuchs are for Leicester.

"Yes, they can join the attack too, as Fuchs showed with his cross for their winner against Southampton, but if he is forward down the left then you know Simpson will drop in rather than getting up the pitch down the right too.

Leicester City's starting XI vs Southampton. The Foxes lined up in a 4-4-2 formation and were unchanged from their 1-0 win at Crystal Palace before the international break

"The whole team all know their jobs, from front to back, and they all work very hard too.

"I am not surprised to find out that Shinji Okazaki is the most substituted player in the Premier League this season, because he runs himself into the ground every time.

Shinji Okazaki has started 23 Premier League games for Leicester this season - and has finished only three of them. He is the most substituted player in the Premier League this season ahead of two other Foxes players - Riyad Mahrez and Marc Albrighton are joint second on 19 apiece.

"It would be easy for the likes of Riyad Mahrez and Jamie Vardy to say 'we are too good for this' but they don't.

"Leicester are still playing the same counter-attacking football they were playing home and away in the first half of the season, but they are getting better at it and I can see why they have only lost three league games out of 32 so far."

'Kante and Drinkwater deny you space as well'

Kante made eight tackles - twice as many as anyone else on the pitch - for Leicester against Southampton and also a team-high four interceptions and 64 sprints. "You can see from his heat map he does not stay like a conventional defensive midfielder," Deeney said. "He goes everywhere to get the ball - he sees it, he goes for it"

Deeney: "When the ball was played forward to me against Leicester, I had to try to bring it down and hold it up with Huth behind me grappling with me and putting me under pressure.

"Then you have also got N'Golo Kante and Danny Drinkwater buzzing around you too.

"Kante was just everywhere against us - I was watching the Southampton game in the Match of the Day 2 production office and he was the same in that match too.

"If he is taking a breather, which is not often, then Drinkwater is there doing exactly the same.

"You don't know where they are coming from, but you know they are coming, so when you have got the ball you are thinking 'I need to lay it off quickly'.

Kante has made more successful tackles - 139 - this season than any other player in the top division in England, Spain, Germany, Italy and France. He has also made 130 interceptions, second only to Aston Villa's Idrissa Gueye in those five leagues

"It works so well because they are both so energetic. If one of them gets forward, then he knows the other has got the legs to cover for him.

"If teams want to come through the middle, they have to get past those two first.

"And, as we saw against Southampton, you don't just have to get past Kante, you have to keep him behind you, which is the hardest part. He has been the best midfielder in the Premier League this season."

'Crosses part of counter-attacking ploy'

Southampton had 33 crosses from open play against Leicester - 28 of them (red arrows in the graphic above) were unsuccessful and only five (shown by green or yellow arrows) found a team-mate. In their last 16 league games, Leicester have conceded 341 crosses, the most in the top flight and 51 more than any other team. Only 61 of those were successful

Deeney: "With Kante and Drinkwater in the middle, in front of their centre-halves, they kind of funnel teams wide, and invite them to cross.

"As I said earlier, Huth and Morgan are waiting for the ball to come in but what makes Leicester different from a lot of the top teams is that their full-backs are prepared for it too.

"Dealing with crosses at the back post might be a weakness with some of those sides who have wingers at full-back because they are less likely to win headers, but Simpson and Fuchs tuck in and know what they have to do.

"They are very effective when the ball comes in and it means that, as a striker, you cannot pull on to them to avoid the big centre-halves either.

"Allowing teams to cross is part of their attacking ploy too.

"Leicester are the kind of team that want you to get a little bit confident when you come forward, thinking you are on top.

"Then, when you commit men forward and are getting excited because you are having all these crosses and think the momentum is with you, that is when they pounce with a quick break using the pace of their forwards."

'Cardboard clappers - the secret weapon'

Leicester have suffered just one home league defeat all season

Deeney: "The support that Leicester get at the King Power Stadium is the kind of thing that will help them get over the line.

"If the team is nervy, like they were at the back end of Sunday's game, then their fans are not stupid - they realised their team needed them and raised the noise levels again.

"Part of that is down to the thousands of cardboard clappers the club leave out on the seats for fans before games.

"I think that actually started in the Championship play-offs in 2013, when we beat them in the semi-finals.

"I remember it being a bit annoying in the first leg at their place when their fans were using them but, now I am playing in the Premier League, I actually appreciated the noise when we went there.

"I don't want to sound too critical, but a lot of fans at some grounds I go to have got cameras in their hands, taking pictures of anything rather than generating any atmosphere during the game.

"At Leicester, it was all about getting behind their team."

Troy Deeney was speaking to BBC Sport's Chris Bevan.