The Whites, missing Kalvin Phillips in the defensive midfield role, went 3-0 down in the first half and left themselves too much to do at the Emirates, before making a real game of it in the second half.
Bielsa moved Pascal Struijk from centre-half into Phillips’s position, shifted Luke Ayling inside from right-back to centre-back and gave Jamie Shackleton a start at full-back.
Bielsa revealed Mateusz Klich played while not fully fit and absolved the three players involved in the reshuffle of any blame.
“I have to mention that Klich played this game while not being at 100 per cent, it was an act of generosity on his part,” said the head coach.
“All teams have absences and not being able to count on Phillips is a disadvantage but I don’t think it was this that unbalanced the game.
“When we were building up from the back we didn’t manage to take the ball into their half cleanly.
“There were no surprises from either managers. They knew how we were going to press and they resolved this. We knew how they were going to press us and didn’t manage to resolve this.
“You could see it clearly the opposing manager prepared the game better than I did.
“I value a lot how we played in the second half.”
Arteta heaped praise on Pierre-Emerick Aubameyang as the striker returned to the Arsenal side to hit his first Premier League hat-trick.
The Gunners captain had not started in five games after leaving the club’s coronavirus-secure bubble to tend to his ill mother.
But he marked his comeback in fine fashion. Operating as the main striker, Aubameyang opened the scoring with a low finish before doubling the lead with a penalty and completing his hat-trick with an early second-half header. Areteta said: “I thought he was superb today, he has been training really good the last week or so, he looked back to normal,” he said.
“He looked really committed in training, really hungry and today he had a great performance, not only for the goals but the way he worked without the ball and the way he worked every Leeds defender, he set the tone.”
Match report: Page 2
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