A fans' group asked supporters to wear Halloween masks to the south Wales football derby in protest at the use of facial recognition technology.
South Wales Police said it was part of a "robust policing plan" when Swansea City and Cardiff City played at the Liberty Stadium on Sunday.
Vince Alm, a spokesman for the Football Supporters' Association Wales, said it opposed the use of the technology.
Police said it would help identify people banned from attending matches.
Five people were arrested for minor public order offences, common assault and invading the pitch.
However the force praised the behaviour of both sets of fans for giving a "very positive impression" of the derby.
Our watchlist, as always, is event-specific and is only being used to reduce the threat of or likelihood of disorder.— South Wales Police (@swpolice) October 27, 2019
Those on our watchlist have previously been convicted of offences at football matches and all have valid banning orders not to attend today's game. #SWACAR
Plans for policing the game have been in place since the fixture was set in June but the use of facial recognition technology angered supporters.
Mr Alm said: "We strongly oppose the police decision to use facial recognition.
"It's just a local football match, yet we haven't had a say and we can't opt out."
Campaign group Big Brother Watch said "intrusive mass surveillance treats all fans as suspects, damages trust and is a total waste of public money".
The group claims it was the first time the technology has been used at a football match since more than 2,000 people were wrongly identified at the Uefa Champions' League final in Cardiff in 2017.
Judges ruled against a shopper from Cardiff who brought a legal challenge against police use of automated facial recognition (AFR) technology earlier this year.
Three people were arrested at the last meeting in February 2014, though none were made following a police operation ahead of the first all-Wales Premier League match in November 2013.
Since then, 41 Cardiff City fans have been handed banning orders while 19 Swansea City supporters have been banned, according to Home Office statistics.
Travel restrictions were relaxed for this latest meeting following the good behaviour of fans in recent games.
Match commander Supt Steve Jones said: "This afternoon was a very successful occasion for all concerned in the months of planning and organisation.
"Both sets of fans contributed to the great atmosphere at the match and the success was as a result of all the careful planning and restrictions put in place."
Swansea moved up to fifth place in the Championship with a 1-0 win, thanks to Ben Wilmott's first-half goal.