Pierre-Emerick Aubameyang admits he has been left frustrated by UEFA regulations which prevent him from turning out for Arsenal in the Europa League.
The Gabon striker arrived at the Emirates Stadium on transfer deadline day in a club-record deal from Borussia Dortmund and has scored three times in five Premier League appearances, including the second in Sunday's 3-0 win over Watford.
But he has not been able to participate in Arsenal's tilt at winning the Europa League due to a rule which manager Arsene Wenger recently insisted "doesn't make sense", with his absence a big miss as winning the competition now represents the club's best chance of securing a return to the Champions League.
Aubameyang is effectively cup-tied despite not playing in the competition this season but, because Dortmund dropped from the Champions League into the Europa League, he is ineligible to represent his new club.
He has therefore been forced to sit out of both legs against Swedish side Ostersund as well as the trip to face boyhood club AC Milan last week, a game the Gunners won 2-0.
"I am really frustrated because the rules are a bit...I don't know how to say in English but I am disappointed because I can't help my team," he said.
"That's life. I have to deal with it. I can't play every three days. When I was in Dortmund, I was playing every three days but now I play once a week or have a long time between games. It is not easy."
Despite being unable to develop a relationship with his new team-mates in every game, Aubameyang is clearly benefiting from playing alongside Henrikh Mkhitaryan - with the former Dortmund pair reunited in north London.
Mkhitaryan laid on Aubameyang's strike against the Hornets before the roles were reversed for the third goal.
Shkodran Mustafi's header had put Arsenal ahead while Troy Deeney, who had accused Wenger's side of lacking "cajones" as Watford came from behind to win the reverse fixture in October, saw a second-half penalty saved by Petr Cech - who went on to keep his 200th Premier League clean sheet.
Aubameyang believes he is now getting towards his best and is keen to keep it up to help relieve the pressure on Wenger, who has seen his position come under scrutiny following a recent run of damaging defeats.
"It is a big win," he said.
"The team did very well and it is a great three points. We needed it. I think the fans are happy, which is really important.
"It was a bit difficult at the beginning but I am feeling better. I didn't play a lot in January so it was difficult to find the rhythm.
"Now I am feeling better. I work hard, I have worked a lot in the last weeks and I am happy because I feel better.
"Of course I am really happy (for Wenger) because I am here because of him. He had the interest in me so I am happy to play for him."
While Arsenal went into the game without a Premier League win since February 3, Javi Gracia's Watford had been enjoying a decent run.
They had won three of their last four, including a 4-1 victory over Chelsea, but Abdoulaye Doucoure conceded the visitors had been taught a lesson.
"You need to work a lot to try and beat this kind of team," the midfielder told Watford's official website.
"I think it is a lesson for us for the next time. I think the penalty is a key point in the game because if Troy scores we come back to 2-1 and the game changes completely but he missed it and we are very disappointed."