The win means that Cardiff will be guaranteed a play off place if they beat Leeds on Saturday lunchtime. It might not even need that. Hull City are 6 points behind Cardiff with a nine goal deficit. A point for Cardiff takes Hull out of the unlikely equation.
Middlesbrough are four points behind but with an 11 goal deficit. Meaning a win and a draw is unlikely to be enough even if Cardiff lose both their games. Middlesbrough simply have to win both their remaining games with Cardiff earning no more than 1 point from both their matches.
Middlesbrough play Southampton on Saturday with the Saints one victory from promotion. A betting man would see Cardiff as big favourites to join West Ham, Birmingham and Blackpool in the end of season lottery.
The win over Derby wasn't as comfortable as the scoreline suggests with Derby the livlier side but a combination of poor finishing from the visitors and a superb display of shot stopping and reaction saves from David Marshall underpinned the foundation for City to take their chances.
The first goal was a clinical finish from Joe Mason (pictured) after Kenny Miller's shot had hit the post. Mason reacted first to give City the lead against the run of play. The opening 20 mins had seen Derby close City down quickly and use their extra pace to cause problems for the Bluebirds.
When City did gain the upper hand they made it pay and some excellent movement from Miller allowed space for the shot but the upright denied him before Mason pounced.
The rest of the first half followed the pattern of Derby pressing and City struggling to stem the flow of Derby pressure.
I felt at half time that we needed to somehow get a 2nd goal to hopefully kill off Derby's enthusiam. What I didn't expect was that Mark Hudson would score from inside his own half.
County keeper Fieldeing had cleared the ball, it bounced to Hudson and as happens on a regular basis the crowd urged him to try the impossible and embarrass the keeper from a ridiculous distance. 999 times out of 1000 the shot is not even attempted but the City skipper took a touch and with the cries of 'Shooooooooot' ringing around the stadium he found the back of the net from 68 yards (declared by the clubs groundstaff). Think back to David Beckham's effort in the 90's and add another 16 or 17 yards.
A real 'I was there' moment as Hudson and his team celebrated.
Derby kept up their pressure but Cardiff were able to see more of the ball and they did what teams have done to us for years. The ground out the win by delaying, fouling and spoiling the play whenever possible and when the chances arose they broke with more conviction. Earnie was on at this stage and became a nuisance and could have grabbed a late goal for himself.
The best chances still fell to Derby but a stunning Marshall save from a header followed by pushing the rebound over the bar helped City see the game out and record what has turned into a massive victory.
Any faint hopes the outsiders for the play offs had was ended with a draws for Brighton, Leicester, Burnley and Watford and defeats for Derby and Leeds.