Chelsea were 1-0 down with six minutes left when Cesar Azpilicueta, who was standing two yards offside, met Marcos Alonso’s flick-on to head home the equaliser.
Ruben Loftus-Cheek punished Cardiff further in stoppage time, leaving Cardiff to count the cost of assistant referee Eddie Smart’s failure to spot that Azpilicueta was clearly offside.
Warnock also felt that Cardiff should have had two penalties, both for Chelsea players holding Sean Morrison’s shirt at set-pieces.
Antonio Rudiger, Warnock added, should also have been sent off for dragging down Kenneth Zohore with the score at 1-1 and the Cardiff substitute through on goal. Rudiger was booked by referee Craig Pawson.
“It’s almost like it’s not who you play, it’s who you get to referee and who is going to have a flag in their hand nowadays, it’s just as important,” Warnock told Sky Sports.
“The best league in the world and probably the worst officials at the minute.
“He (Smart) is saying that Willian blocked his view, but it wasn’t a six inches one. Either side you should be able to see he’s two yards offside.
“It’s soul-destroying really. I can understand why the lads are down.”
Cardiff took the lead against lacklustre Chelsea in the first minute of the second half.
Victor Camarasa struck a splendid volley and Cardiff, who are 18th and in the final relegation place, looked as if they would cut the five-point gap on Brighton, Burnley and Southampton above them.
“If I was a Burnley, Southampton or Brighton fan it’s the best thing that could have ever happened,” Warnock said.
“It’s knocked our lads down, they are flat.
“We’ve worked on things for the last three weeks and one of them is coming out at corner kicks and leaving a man in.
“The lads have just said ‘what we do now gaffer? What’s the point?’
“You’ve got to hope the linesman can see it. VAR has got to be the answer to help them out, it would have sorted the goal out within seconds.”
Chelsea’s win took them to within one point of fourth-placed Manchester United and kept alive their hopes of a Champions League spot.
But manager Maurizio Sarri, who left star forward Eden Hazard on the bench until the 53rd minute, was a target for the travelling supporters during the second half.
The Chelsea fans sang ‘we want Sarri out’ and ‘you don’t know what you’re doing’ before the late goals.
Sarri said: “I don’t want to answer, but I can understand the reaction of the fans.
“But it was probably best for them to wait until the end of the match. I am getting used to this and for me, it’s not a big problem.
“I just have to work to change their opinion. If I win matches, then the fans will be happy.
“We were lucky with the first goal. But I think we deserved to win and, sometimes during a season, you need to win matches like this.”
Arsenal return to Premier League action on Monday as they welcome Newcastle to north London.
Newcastle are seven points above the relegation zone, possibly safe already, though they can’t afford to think so. Arsenal, meanwhile, need to keep pace with their top four rivals.
Here are the talking points for the game.
WILL ARSENAL BE RUSTY OR RESTED?
Arsenal have had a longer break than most Premier League teams, since they didn’t play on the weekend before the international break thanks to their early elimination from the FA Cup while their scheduled opponents, Wolves, were busy beating Manchester United in the quarter-finals of the competition that weekend.
By a quirk of the schedule they’re also playing the last game of this game week, one or in some cases two days after everyone else, and a full 18 days since they last kicked a ball in anger.
The extra day could help players like Aaron Ramsey and Granit Xhaka be fit for this game, which would be a welcome boost. Newcastle have showed in recent weeks that they are no pushovers and though Arsenal are formidable at home, this has all the makings of a potential banana-skin game. They may be well-rested, but they can’t afford to show any rust.
ARSENAL NEED TO MAKE THEIR MARK IN TOP FOUR RACE
By most pundits’ estimations, Arsenal have the inside track on their rivals in the top four race. They play no other top-six side the rest of the season, though Monday’s game is one of only three remaining at home in Arsenal’s final eight league fixtures.
Those three home games are all against teams in the bottom half of the table, starting with Rafael Benitez’s outfit, and though no team can afford to be taken lightly – Newcastle and Crystal Palace, another of Arsenal’s remaining home opponents, have both beaten Man City this season – Arsenal are undoubtedly targeting nine points from those games.
Only City and Liverpool have better home records than Unai Emery’s side this season. And this weekend, Arsenal play after all of their top four rivals, which can add to the pressure but also makes it abundantly clear what’s expected of them. This is the perfect chance to make a statement.
It's the business end of the season, who out of these four sides battling for Top 4 will finish with the CL qualification!— Arsenal Editor (@Arsenal_Editor) March 30, 2019
I think on paper we have the easiest run in, with only Wolves away being a tricky tie other than that Top 4 is pretty much in our hands to lose! pic.twitter.com/Mx2ThYwugh
CAN BENITEZ BREAK HIS DUCK?
For all that Benitez has achieved as Newcastle manager, he could make a bit of personal history on Monday. The Spaniard has never managed a win away from home in the Premier League at Arsenal, with two draws the best he’s done in seven previous visits to the North-London club.
Across competitions in 2019, Arsenal and Newcastle have actually lost the same number of games, five, which doesn’t reflect too well on the Gunners; true, two of their losses came in Europe, where Newcastle haven’t played a competitive fixture in six years, but those were against BATE Borisov and Rennes.
Their home form has been superlative all season, however, which makes it unlikely that Benitez breaks his duck on Monday. But Newcastle have acquitted themselves well in away losses against City, Chelsea, Tottenham, and United – where they led 2-0 – this season. Is this the game where they finally break through?
🔵 Man City's record across all competitions in 2019:— Coral (@Coral) March 30, 2019
Rafael Benítez's Newcastle the only side to beat them this year. pic.twitter.com/cTqMFeA22H
Unai Emery has revealed Arsenal will consider handing Danny Welbeck a new contract with the striker on course to return to training before the season’s end.
The 28-year-old broke his right ankle in November’s Europa League draw at home to Sporting Lisbon and – while he is unlikely to return this season – Emery insists he is “progressing very well”.
In his absence Arsenal have steadily improved as they have adjusted to their new manager’s methods, with fellow strikers Alexandre Lacazette and Pierre-Emerick Aubameyang becoming particularly key amid a wider expectation Welbeck would leave this summer.
His contract then expires, five years after his arrival from Manchester United, and Emery said: “He’s progressing very well.
“He is working and starting to touch the ball and to work on the pitch. His progress with such a big injury is going very well.
“It’s difficult for him to play matches this season but he is progressing very well and maybe the doctor will tell us he can come train with us in the last weeks of this season.
“After, his individual thing is to speak with the club (about his future).”
Suggestions Welbeck could yet have a future at Arsenal also come with the 47-year-old Emery convinced of the value of his team featuring English players.
Jack Wilshere’s departure last summer for West Ham, Welbeck’s injury and Calum Chambers’ presence on loan at Fulham has contributed to the fact that they had no players in the past England squad.
The Spaniard – whose team on Monday host Newcastle – said: “Every (English) team needs English players.
“Danny has his injury now. He was going with the national team and we were happy for him and the national team.
“(Promising English players) are now in (Arsenal’s) under-18s, under-19s, under-20s and under-21s teams.
“We have a lot of players with the possibility to grow up with us and be part of our future, and also with the national team.”
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