Despite a dominant performance, Chelsea lost their 100% record under new manager Antonio Conte after drawing 2-2 against Swansea at the Liberty Stadium.
The Blues deservedly took the lead through Diego Costa's excellent strike in the 18th minute, and they needed their Spanish striker to rescue a point nine minutes from time following a three-minute period in which Chelsea conceded twice.
A stranded Thibaut Courtois brought down Gylfi Sigurdsson in the area and the Icelandic playmaker coolly converted the resulting penalty to equalise - but it was Swansea's second goal which produced the real controversy.
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Midfielder Leroy Fer appeared to clearly foul Chelsea's Gary Cahill, before dispossessing him and running clear to squeeze his shot past Courtois and bundle the ball over the line.
The decision arguably cost Chelsea the three points, and following referee Andre Marriner's decision not to award a foul, Cahill, Conte and Cesar Azpilicueta have all had their say.
Cahill took to Twitter to vent his frustrations, uploading a clip of the video which you can see above, showing the contact made between Fer and himself, as well as Marriner shaking his head at Cahill's protests.
Shortly after that, the 30-year-old England international posted a one-word but extremely powerful tweet:
What does Conte think?
Conte also responded to the decision which led to the Swans' second goal. "People looking at the second goal can see that the referee made a mistake - but this can happen. I've not spoken to the referee. It's a big mistake," he said.
Speaking about the match as a whole, the 47-year-old Italian admitted, "It's very difficult to talk about the game because we lost two points. We were leading 1-0 and created a lot of chances to score another goal."
"We are disappointed because the performance was very good in terms of our intensity and because we played good football," he continued.
Azpilicueta frustrated by "clear foul"
One of Cahill's defensive partners Cesar Azpilueta also criticised the referee for what he believed was a "clear foul" on his teammate.
The 27-year-old Spaniard told Sky Sports, "It's a huge disappointment because we had control of the game for most of the time. Their two goals came from mistakes and we were disappointed to only get one point.
"The second one is a clear foul. The free-kick was clear but the ref made that decision. The reaction of the team was very good. At 2-2 we had chances to get a third. The spirit was good but we are disappointed to only get one point."
Did YOU think Cahill got fouled in the build-up to Swansea's second goal? Leave YOUR opinion in the comments box below!