At times during the day, the on-field temperatures reached almost 60-degrees Celcius, and Penrith - one of Sydney's Western Suburbs - was the hottest place in the world on Sunday. The Bureau of Meteorology confirmed on Monday that Penrith had reached the highest temperature on the planet in the past 24 hours when it reached 47.3 degrees on Sunday afternoon.
With the Australian Open fast approaching, it poses the question - how hot is too hot to expect athletes to perform?
The A-League football competition also uses the Wet Bulb Globe Temperature, which considers temperature, humidity, wind speed and the angle of the sun to decide on whether conditions are playable or not.
In early 2017, Football Federation Australia postponed a match between the Newcastle Jets and Melbourne Victory two days ahead of time due to the weather bureau forecasting a WGBT of 34, which was 6 over the limit for a match to be played.
More recently, the W-League final which was scheduled to be played before Wellington Phoenix's match against Melbourne City in Melbourne on Saturday was postponed for a day so it could be held later in the day and out of the early afternoon heat.
For the Australian Open - it's 40C and a WBGT reading of 32.5.
The Melbourne tournament implemented an extreme heat policy in 1998 after discussions with players regarding playing conditions.
The policy stated that all matches be stopped if temperatures reached 40C or above. This replaced the ruling that begain in 1988 where the roof of Rod Laver Arena could be closed for day matches in high temperatures.
In 2002, the heat threshold was dropped to 38C before being dropped to 35C a year later.
After the extreme heat policy came into play in both 2006 and '07 events, it was again altered in 2008 to allow matches in progress to be halted at the conclusion of the set. Prior to that a match already underway had to be completed.
The policy was further changed in 2008 to allow play to be stopped only at the discretion of the tournament referee.
The policy saw a number of matches halted in the 2009 tournament, however it came under fire in 2014 when play wasn't halted despite high temperatures because the humidty was at a high enough level, taking into account the WBGT.
Following the 2014 event, the threshold was again raised to 40C from 35C, while the WBGT temperature threshold was increased to a 32.5 reading.
In 2016 the ruling was needed again despite the raised threshold as temperatures soared as high as 42C.
