Manager Mikel Arteta was furious at two refereeing decisions after Arsenal suffered a 1-0 defeat to Internazionale in the UEFA Champions League on Wednesday.

The Gunners were denied a penalty as Inter goalkeeper Yann Sommer connected with the head of Mikel Merino, only for Merino to concede a spot kick for handball shortly afterward.

"I don't understand [the handball decision]," Arteta said. "There is no danger at all. You cannot react because the ball is very close. But OK. They decide that is a penalty.

"But if that is a penalty then the one on Merino where he [Sommer] punches him in the head has to be a penalty 1,000%. These are the margins in this game and it's very difficult to accept."

But was Arteta's anger misplaced, or should the VAR have stepped in?

Inter Milan 1-0 Arsenal

Possible penalty: Challenge by Sommer on Merino

What happened: The game was in the 28th minute when Gabriel Martinelli swung a cross into the box from the left flank. Mikel Merino got to the ball first but headed over, with goalkeeper Yann Sommer then making contact with the Arsenal player's head in attempt to punch clear. Romanian referee Istvan Kovacs signalled for a goal kick and a possible penalty was checked by the VAR, Christian Dingert.

VAR decision: No penalty.

VAR review: Goalkeepers have a right to rush out and challenge for the ball with their fists, yet at the same time they must be aware of the players who are around them.

It's hard to be sure, but Sommer might have got a slight touch on the ball before it came off Merino's head. Even so, that would not remove the possibility of a penalty being awarded if the challenge was deemed to be reckless or dangerous.

In UEFA competitions, where there is a much lower threshold for fouls, we'd expect to see a spot kick awarded in a situation like this. So you can absolutely understand Arteta's frustration.

Sommer makes full contact with Merino's head, clearing pushing it back, and the Arsenal player then went to ground holding his head.

The VAR has decided that this is normal football contact; a goalkeeper collision as part of a genuine attempt to play the ball and there wasn't enough in it to be deemed a reckless act.

At Euro 2020, France goalkeeper Hugo Lloris conceded a penalty when he came out to punch and caught Portugal midfielder Danilo in the head.

At the 2022 World Cup, Argentina were awarded a penalty against Poland when goalkeeper Wojciech Szczesny caught Lionel Messi with an outstretched arm. Szczesny came out to claim a cross in the 36th minute, Messi got to his head to the ball first, but Szczesny then collided with the striker. The VAR, Paulus Van Boekel of Netherlands, advised a penalty review. But the contact was so slight that the decision seemed harsh.

Looking at league play last season, Chelsea goalkeeper Robert Sánchez came out for a cross and clattered into Arsenal's Gabriel Jesus. The referee didn't give the spot kick on the field, and the Premier League's Key Match Incidents Panel said the only thing which saved that from being a VAR mistake was an offside player in the buildup.

Possible penalty overturn: Handball by Merino

What happened: Inter Milan were awarded a penalty in first-half stoppage time when Hakan Çalhanoglu played a ball into the area, and when Mehdi Taremi tried to help it on it hit Merino's hand. Referee Kovacs pointed to the penalty spot.

VAR decision: Penalty stands, scored by Çalhanoglu.

VAR review: Fans of English football have become insulated from handball penalties this season. So far in the Premier League only one spot kick has been awarded across 100 matches -- by the VAR against Aston Villa's Matty Cash at Fulham.

Referees are putting all the focus on a player having the right to actually have arms, deeming handball should only be penalised if a player's arm is completely outside the body and creating a clear barrier. Villa's Cash had his arm fully extended, but even with there was doubt over proximity.

The Premier League is certainly the outlier, with the Champions League having the highest frequency of handball penalties of any competition, though marginally ahead of Ligue 1.

Merino was stood right next to Taremi but his arm was in a raised position and it blocked the path of the ball, so under UEFA's definition that is expected to be penalised.

The main frustration is that many competitions now have their own interpretation of the wording, either lenient like the Premier League to really strict like the UCL and France. It will be hard for Arsenal fans to accept as the league has moved back to the interpretation used before the 2018 law change (which caused such a huge upsurge in spot kicks.) Yet it's effectively a two-tier law, as Arsenal discovered on Wednesday.

Possible red card: Arteta for interfering with play

What happened: The game was in the 63rd minute when the ball ran along the touchline and, as Matteo Darmian moved toward it, Arteta picked it up before it went out of play. Referee Kovacs showed the yellow card, but should it have been red?

VAR decision: No red card.

VAR review: By the letter of the law this should be a red card, as Law 12 states: "Sending-off offences include (but are not limited to) entering the field of play to interfere with play."

We've seen two such red cards this year in British football, for West Bromwich Albion manager Carlos Corberán and Kilmarnock boss Derek McInnes.

The referee chose to use his discretion and only show Arteta a yellow card, as the ball looked to be running out of play, but by rights this should have been a red.

However, the VAR is not charged with intervening in such matters where the referee has obviously seen the incident but chosen not to show a red card.

Club Brugge 1-0 Aston Villa

Possible penalty overturn / red card: Mings handball

What happened: Club Brugge were awarded a penalty in bizarre circumstances in the 50th minute. Aston Villa had a goal kick, and goalkeeper Emiliano Martínez played it to defender Tyrone Mings ... who thought play hadn't started yet and picked up the ball. Referee Tobia Stieler pointed to the penalty spot, but took no disciplinary action against Mings.

VAR decision: No red card. Penalty stands, scored by Hans Vanaken.

VAR review: A crazy situation -- especially when you consider we saw a very similar situation in April which didn't result in a penalty.

In the earlier example, Arsenal were playing Bayern Munich in the quarterfinal. Goalkeeper David Raya had the ball in the centre, he then passed to Gabriel, who picked the ball up and placed it down again before passing it back to Raya. Swedish referee Glenn Nyberg chose to use his discretion (the spirit of the law, as noted in Law 5, gives a referee some leeway in certain circumstances to manage the game) and allowed the kick to be taken again, rather than giving a penalty.

That wasn't the case for Villa, with Stieler choosing to give the spot kick -- and many would argue that Nyberg was wrong in not doing so too.

There is one key difference: In the Arsenal game there was no pressure being put on the ball by a Bayern player, so you could argue this was an inconsequential mistake and the referee was fair to allow the retake. In the Villa game, Ferran Jutglà ran into the area to close down Mings at the moment Martínez played the ball.

Mings was already on a yellow card and this was a deliberate handball, so why wasn't he shown a red card, or at least a second yellow? That's the real question for the VAR because a penalty is undoubtedly correct in law.

Deliberate handball isn't in itself an offence that requires disciplinary action, just like when a goalkeeper handballs outside the box. It's all about the impact on the opposition.

Stieler could have chosen to book Mings if he felt Jutglà was being prevented from playing the ball, but the VAR cannot rule on yellows.

It then comes down to a red card, and whether the VAR felt the Mings handball was an offence of denying an obvious goal-scoring opportunity (DOGSO). Jutglà was moving in on the ball but it was not running with pace, so he would definitely get to it if Mings hadn't handled. But it's not a classic case of DOGSO where an attacker is going past a defender making a foul, Mings would still be there to make a challenge. So the only real argument is for a yellow for possibly stopping a promising attacker, which the VAR cannot give.

Even though Jutglà was running in to close down, Mings still had plenty of time so his decision to pick up the ball is even more perplexing. He must not have thought Martínez had put the ball in player. But he could easily have been given a second yellow by the referee.

Whatever you think about the merits of the two individual incidents, it's difficult for fans to make sense that the two can have opposing outcomes -- one a retake and the other a penalty.