Arsene Wenger was happy to take his players' word that the award of Arsenal's late penalty against Southampton was correct.
The Gunners came back from 1-0 down to win 2-1, Santi Cazorla scoring deep into injury-time after substitute Olivier Giroud was brought down in the box by Jose Fonte.
Southampton surrounded referee Bobby Madley after the decision, but the Gunners players had no doubt.
Wenger said: "I haven't seen (the penalty) again, but they tell me in the dressing room it was a penalty - a 100 per cent penalty.
"When you lose the first home game you cannot afford to drop points in the second. It is a win after Watford and, if you can put a few wins together like we have, we will be more confident."
Forward Lucas Perez and defender Shkodran Mustafi made their Gunners debuts, but Wenger admitted they were not at their best.
He said: "I feel both are short, they lack competition and their second half was much better than their first.
"They were a bit surprised by the pace and commitment of the Premier League, but they will adapt to that.
"They were a bit on their nerves in the first half, but in the second half they were much better."
Southampton manager Claude Puel was disappointed his side conceded so late in the game after taking the lead in the first half.
A Petr Cech own goal put Saints in front after 18 minutes, but, after Laurent Koscielny levelled on 29 minutes, Southampton's confidence appeared to take a hit.
Cazorla's penalty was the third Southampton have conceded so far this season in just four games and Puel is not happy with that statistic.
He said: "I am angry for my players. I don't like to speak of the decision of the referee, but we have conceded, in four games in the championship, three penalties.
"I want to stay with the positives of this game. I think we played fantastic in the first 30 minutes.
"We played with good possibilities, we scored. Perhaps at the end of the first half we dropped back, but it was a good game and my players have been bright.
"We had (chances) to score and win this game against a good team and a draw would have been a (reward).
"It is a disappointment for my players to lose this game in this condition."