Following Saturday's defeat to Crystal Palace and a touchline incident with James McArthur, Leicester started the week having been forced to deny reports that Pearson had been sacked.
And, while his side showed flashes of quality at the Emirates Stadium that included Andrej Kramaric's first goal for the club, Pearson was again left to lament defensive errors as they fell to a fourth consecutive league defeat.
Theo Walcott - one of three Arsenal changes from their north London derby defeat to Tottenham - made it two before the break as he seized on Mark Schwarzer's parry before Kramaric gave the visitors brief hope.
However, Arsene Wenger's men were not to be denied a return to winning ways as they moved back into the top four, while Leicester's loss was made worse by victories for fellow strugglers Hull City and QPR.
Wenger’s men got their reward courtesy of Koscielny, as the France international lost marker Wes Morgan with ease and finished Ozil's corner.
Koscielny’s defensive partner, Per Mertesacker, was then required to clear a dangerous cross from Paul Konchesky eight minutes before the interval with Pearson’s side again demonstrating some attacking threat of their own.
However, despite their forward promise, Leicester were again let down by a defensive mishap four minutes before the break when Schwarzer parried Ozil's strike into the path of Walcott, who made no mistake with the follow-up.
While Ulloa's presence made an impact, it proved too little, too late for Pearson and Leicester.
Meanwhile, Wenger's main frustration, other than a nervy second-half display, will be an apparent injury suffered by Aaron Ramsey - who lasted just nine minutes after coming off the bench.
