Andre Marriner focus
Referee Andre Marriner took charge of his first game since the incident which saw Manchester City striker Sergio Aguero handed a three-match ban for violent conduct as Chelsea and Swansea played out a 2-2 draw at the Liberty Stadium.
Aguero was charged retrospectively by the Football Association after appearing to elbow West Ham's Winston Reid in City's 3-1 win on August 28, with referee Andre Marriner and his fellow officials missing the incident during the match.
Here, Press Association Sport looks at Marriner's performance on Sunday.
16: Cesar Azpilicueta blocks Ki Sung-yueng as he is bursting forward, with Marriner awarding Swansea a free-kick. Although there was contact, the decision not to show a yellow card seems fair.
26: Marriner has no choice but to show Fer the first yellow of the match as he brings down Costa by the halfway line in an attempt to stop a Chelsea counter-attack.
35: Fer fouls Nemanja Matic as he runs down the left wing, conceding a free-kick near the corner flag. Marriner speaks to players in the box to warn them about pushing and shoving ahead of the free-kick.
39: Willian goes down in the box and appeals for a penalty but Marriner allows play to continue and Swansea go straight down the other end.
41: Costa goes into the book for a foul on Leroy Fer.
42: Swansea see another of their players pick up a booking as Federico Fernandez fouls Costa on halfway.
48: Costa goes down following a clash of heads with Jordi Amat. The Swansea defender goes into the book and Chelsea are awarded a free-kick.
52: Costa is fouled by Amat once more. A free-kick is given some 30 yards from goal.
57: Amat fouls Ivanovic and gets a talking-to from Marriner, who also speaks to Swansea captain Jack Cork but decides not to send Amat off.
58: Marriner points to the spot after Thibaut Courtois slid in and fouled Gylfi Sigurdsson. The referee also books Courtois.
62: Fer makes contact with Cahill as he dispossesses the Chelsea defender in the build-up to Swansea's second. Cahill appeals for a foul but Marriner controversially allows the goal to stand.
81: Costa's foot is very high as he scores Chelsea's equaliser, but Marriner does not penalise him and lets the goal stand.
89: Eden Hazard fouls Swansea substitute Modou Barrow 40 yards from goal in a bid to amends for a slip which saw him relinquish possession. The Chelsea man goes into the book.
90+2: John Terry is booked for fouling Fer near the halfway line after Hazard had given the ball away.
90+3: The Swansea fans appeal for a penalty as Ki is held by Cesc Fabregas in the box but Marriner, who had a great view, gives nothing.