Bayern Munich scored either side of halftime through Michael Olise and Harry Kane but had to endure late pressure from hosts Celtic before securing a 2-1 victory
Kylian Mbappe was in inspired form, scoring twice to guide Real Madrid to a comeback 4-1 win over visitors Las Palmas on Sunday.
Liverpool took another step towards the Premier League title with a 2-0 win at Manchester City.
European soccer's governing body has so far resisted implementation of the VAR system, which allows key incidents to be reviewed with the use of video replays and was used at the World Cup in Russia this year.
Chelsea recovered to beat West Ham United 2-1 to jump to fourth place in the English Premier League on Monday.
Images from Saturday's FA Cup quarter-finals.
Apex football body FIFA and the International Football Association Board (IFAB), which set the rules, have issued new guidelines ahead of the restart of the Bundesliga.
The sight of Tunisia defenders wrestling England's Harry Kane to the ground in the penalty area without punishment during Monday's World Cup Group G match has raised more questions about the worth of the Video Assistant Referee (VAR).
The Video Assistant Referee (VAR) was used for the first time in a World Cup final to award France a 38th-minute penalty which Antoine Griezmann scored to give them a 2-1 lead over Croatia.
Manchester City had a late goal from Gabriel Jesus ruled out by VAR video review as they drew 2-2 at home to Tottenham Hotspur on Saturday -- their first league home game without victory in nearly eight months.
That kept Real top of LaLiga on 50 points, one ahead of Atletico in second who missed a chance to leapfrog them. Barcelona, third on 45 points, visit Sevilla on Sunday with a chance to close the gap in the title race.
Juventus substitute Cristiano Ronaldo was denied a stoppage-time winner by VAR as Udinese came from two goals down to snatch a 2-2 draw in their thrilling Serie A season opener on Sunday.
A summary of Thursday's Europa League quarter-finals second-leg.
A summary of Saturday's action in the LaLiga, Serie A and Bundesliga.
A stoppage-time finish from Rayan Cherki earned Olympique Lyonnais a dramatic 2-2 draw with Manchester United in the first leg of their Europa League quarter-final.
A round-up of Saturday's fifth round action in the FA Cup
Kylian Mbappe and Brahim Diaz also struck for Real, to cancel out a double from City's Erling Haaland
Julen Lopetegui's side were awarded a penalty early in the game after a VAR review determined forward Nolito had been fouled by Valladolid's Javi Moyano as he shaped to shoot, even though his team mates had barely appealed for a foul.
Some reporters later returned to the conference room, although local press strongly condemned the player's actions, adding to criticism of the team's poor form this season, which has left them sitting 10th in the Liga MX table.
Wolverhampton Wanderers had a goal controversially ruled out by VAR as they were held to a 0-0 draw at home to Leicester City, who finished with 10 men, in the Premier League on Friday.
Champions Manchester City could only muster a 2-2 Premier League draw with Brighton & Hove Albion on Saturday.
The following factbox details five times a Video Assistant Referee (VAR) made an impact at the World Cup.
Images from the Serie A and La Liga matches played on Saturday.
Poland striker Robert Lewandowski scored from his second attempt from the penalty spot against France.
A round-up of Saturday's action in LaLiga, Ligue 1, Serie A and Bundesliga.
IMAGES from the English Premier League match played between Arsenal and Chelsea at Emirates Stadium in London on Sunday.
Carlo Ancelotti's side were then reduced to 10 men in the 79th minute when Vinicius Jr was shown a straight red card for slapping Valencia goalkeeper Stole Dimitrievski.
European soccer's governing body opted against using VAR this season, despite the technology being employed by major European leagues in Spain, Italy and Germany, and the World Cup in Russia this year.
Manchester City defender John Stones headed a controversial stoppage-time winner in a 2-1 victory at Wolverhampton Wanderers on Sunday that took them top of the Premier League and set a club record of 31 league games unbeaten.
Manchester City forward Gabriel Jesus became the first player to have a goal disallowed by the Video Assistant Referee (VAR) in the English Premier League.
Barcelona thrashed Real Betis 5-1 on Wednesday to book their spot in the Copa del Rey quarter-finals.
Amad Diallo struck a late equaliser as Manchester United made a mockery of their recent form to hold Premier League leaders Liverpool
'People sitting in the stands need to know what the rules are. Who is refereeing the game? We need to know. People deserve to know what are the rules of the game and the game belongs to the people.'
Lucas Bergvall scored his first goal for Tottenham Hotspur to give his side a surprise 1-0 victory over holders Liverpool in the first leg of their League Cup semi-final on Wednesday.
Tottenham Hotspur gained a slender advantage in their League Cup semi-final against London rivals Chelsea as Harry Kane's penalty earned them a gritty 1-0 first-leg win.
Lewandowski strike gives Barcelona 1-0 win over Alaves
A summary of Sunday's action in the Premier League.
IMAGES from the Premier League matches played on Sunday
News of all that's transpired on and off the football field
A round-up of Wednesday's UEFA Champions League last-16 first leg matches.
