Cheating is rife in football and players get up to many dirty tricks in their attempts to win a match at any cost.
Calls are growing for video technology to be introduced to help referees reach the correct decision, although many methods cunning players use to dupe officials will still slip under the radar.
Technology might have prevented referee Bjorn Kuipers from being tricked by Oscar's play-acting into sending off Zlatan Ibrahimovic as Paris Saint-Germain eliminated Chelsea from the Champions League on Wednesday in London. It might also have seen Chelsea awarded a penalty and striker Diego Costa sent off.
Here is a look at some of the ways players cheat to try to win football matches:
The majority of players will do anything to get an advantage, and badgering the referee in an attempt to get a favorable decision is a popular ruse.
This was noticeably seen when Zlatan Ibrahimovic was sent off in Paris Saint-Germain's draw at Chelsea, which sent the French team through to the quarterfinals of the Champions League on Wednesday.
After Ibrahimovic's foul on Oscar, Chelsea's other outfield players all surrounded Kuipers trying to persuade him to get his red card out.
Ibrahimovic branded them 'babies' for their reaction, while their actions were resoundly criticized and labeled disgraceful. However, Chelsea captain John Terry — who led the charge towards Kuipers — argued that he and his teammates were simply doing what every other team does.
One of the most common tricks in the book. Players fall over when a rival player comes near them in an attempt to win a penalty or a free kick and get their opponent into trouble.
Some players pull this trick so often that they get a reputation in the game for being a diver — which can then work against them when they go down under a genuine foul.
This is perhaps one of the simplest cons for video technology to combat. Also, simulation, as it is known, is now an offence resulting in a yellow card and referees are becoming smarter at spotting the deliberate dives.
Diving is not the only piece of pretense footballers use in their attempts to cheat. Feigning injury is also a common ruse as players pretend to be hurt in order to get opponents booked or sent off.
Brazilian legend Rivaldo was roundly castigated after tricking the referee into showing a red card to Hakan Unsal during the closing stages of a World Cup group match between Turkey and Brazil in 2002.
Unsal kicked a ball in frustration at Rivaldo as the Brazilian waited to take a corner in stoppage time. Although it hit his shin, Rivaldo went down clutching his face and Unsal was dismissed.
Rivaldo was later fined £5,180 ($7,350) by FIFA.
This is a trick that has been going on for years and there are many ways for players to run down the clock if they are leading late in the game as they attempt to minimize the time the opposition team has to level.
One of the most common methods of time wasting is to delay the taking of free kicks, corners and throw-ins — both their own and the opposition's. Players may also feign injury or be slow to leave the field after being substituted.
Managers also get in on the act by making late substitutions, while ballboys help too by being slow to return balls. Sometimes ballboys go missing altogether in the final minutes if the home team is winning.
Any acts with the sole purpose of wasting time are considered cautionable offenses but are often difficult to pinpoint.
If players think they can get away with it, they will try.
There have been two famous incidents of handballs proving crucial on the international stage, with the most notorious perhaps being Diego Maradona's 'Hand of God.'
Argentina beat England 2-1 in the 1986 World Cup quarterfinal thanks in part to Maradona's controversial opening goal, with the diminutive forward using his hand to palm the ball over England goalkeeper Peter Shilton.
Another notorious incident occurred in the playoffs for the 2010 World Cup, when France forward Thierry Henry handled the ball to set up William Gallas' decisive goal against the Republic of Ireland.
In London on Wednesday, PSG's Thiago Silva for some unknown reason deliberately handled the ball in his own penalty area. Chelsea scored the penalty and almost knocked PSG out.