It’s been quite the week for Leicester City and their manager Claudio Ranieri. Mounting speculation of the sack; an official declaration of ‘unwavering support’ for the Italian; rumours of a change in post-match dietary regime (from chicken burgers to pasta); and Ranieri’s impassioned defence of his struggling ‘warriors’.

Hostile and unforgiving, the Premier League holds no punches - not even when it comes to an individual as noteworthy and charismatic as Claudio. With the Foxes now ignominiously fighting for survival at the bottom of the table, the history maker has subsequently found himself backed into a corner, forced under the spotlight and scrutinised to the point of interrogation.

Which is why it will have come as a relief for all involved at Leicester City Football Club to see the champions battle their way past Derby County on a bitterly cold evening at the King Power Stadium, one fraught with numerous officiating mistakes, to reach the fifth round of the FA Cup.

Ranieri was under pressure, despite the club's statement backing him this week (Getty)

It was by no means easy, with Abdoul Camara's equaliser cancelling out Andy King's opener to take the game to extra-time, but late goals from substitute Wilfred Ndidi and star man Demarai Gray handed Leicester a much-needed pick-me-up ahead of Sunday’s Premier League crunch match against Swansea City.

With a total of 18 changes made to the two teams from their previous fixtures, it was a replay neither side apparently wanted but the relatively high tempo of the game suggested both teams meant business.

It was the visitors who enjoyed the first significant passage of play, trying Leicester at their own game in the 14th minute. Breaking on the counter down the left, Ikechi Anya soon found himself with possession and after weaving his way past his opposite man, delivered a testing cross into the Leicester box. Nick Blackman was on hand to challenge but Marcin Wasilewski interjected to clear the danger.

As has been the case for much of their season, Leicester’s defence failed to instil much confidence in the home fans. Momentarily lapses in concentration and poor decision making ran through the Foxes back line like a stripe through rock.

Such shortcomings were clear to see as Yohan Benalouane notably found himself caught in possession four minutes after Blackman's chance, allowing the visitors to mount a promising attack down the right. A corner ensued and Leicester appeared shaken as the delivery bounced precariously through the box, untouched by both blue and white shirts, before being recycled on the right. Wrapping his foot around the ball, Camara floated his effort towards the top-left corner of the Leicester goal but failed to find the target.

King broke the deadlock just after half time (Getty)

Still, while their team-mates at the back struggled to find their rhythm - excluding the effervescent Ben Chilwell who continues to impress in a Leicester shirt - the home side’s front men offered threat going forward.

Gray was Leicester’s stand-out player in the game. Unafraid to drift inwards, the 20-year-old was pivotal in providing the Foxes with a sense of urgency and dynamism going forward. Indeed, it was the youngster who drew the first yellow card just six minutes into the game after forcing Cyrus Christie into a reckless challenge with his silky feet.

But it was a penalty appeal 20 minutes later that had the home fans up in arms as Ahmed Musa was seemingly brought down on goal by Derby’s Jason Shackle. Referee Michael Jones waved on but replays appeared to suggest that Leicester deserved a kick from the spot.

The Foxes remained patient nonetheless and it wasn’t long before they were rewarded with their best chance of the first half. It was Gray again, bursting into the Derby box, gliding past Max Lowe, before releasing a low-driven cross from the right. Musa reached in desperation but was centimetres short of contact.

Jacob Butterfield finished the first half with a respectful low-driven effort but both teams headed into the break knowing more could be done.

Abdoul Camara's free kick was deflected in for the equaliser (Getty)

Leicester’s first goal came almost instantly after the restart. Picking up the ball on the left, Gray cut inwards, losing his man in the process, to then pick out Marc Albrighton at the far post with a well-placed delivery. Craning his neck to make connection, the winger nodded the ball back across the goal to an unmarked Andy King who did the rest from five yards out.

Still, Derby refused to roll over. A series of back-to-back free-kicks followed for Derby, courtesy of more dodgy Leicester defending and questionable officiating, and the Rams soon found their equaliser. Striking from 20-odd yards out, Camara’s dead ball effort took a fortuitous deflection off Chilwell to draw the score level at 1-1.

The Foxes continued to press on nonetheless, looking for a way past a defiant Derby side, and although the remaining 30 minutes were largely dictated by the home side, Mclaren’s men stood strong.

King came closest with five minutes left of normal time, his headed effort sailing tantalisingly close to Jonathan Mitchell’s right-hand post. Moments after that, Mitchell avoided a blatant red card for handling the ball outside of his box after rushing to meet a clipped Chilwell ball over the top. More inaction from Jones and further Leicester City indignation, but the score remained 1-1.

Demarai Gray scored the important third for Leicester (Getty)

But Leicester’s talent shone through in extra-time, with Ndidi and Gray landing the hammer blows as the Foxes finally asserted their dominance in a game of football that had very much become a war of attrition.

Picking up play from fellow substitute Riyad Mahrez, Ndidi ran true and straight down the centre of Derby’s final third, unleashing a fire-cracker of a shot that caught the inside of the right-hand post before nestling into the opposite side netting.

Gray sealed the deal for the Foxes with six minutes to go, again exhibiting the sort of dizzying foot work that is seeing him morph into last season's Mahrez as he danced his way past two Derby defenders inside their own box, picking out the top right corner with a delicious curled effort. 3-1 and at long last a spot in the fifth round of the FA Cup.

Leicester City: Zieler, Amartey, Wasilewski, Benalouane, Chilwell, Mendy, King, Albrighton, Kapustka, Gray, Musa.

Derby County: Mitchell, Christie, Keogh, Shackell, Lowe, Butterfield, Johnson, de Sart, Camara, Blackman, Anya.