The England international marked his first Premier League start since August with both goals as Arsene Wenger's side moved back above Manchester City in the Premier League table
Arsene Wenger's men were made to work hard against a typically resolute Palace, but victory sees them return to the summit, though Manchester City can reclaim top spot if they beat Chelsea on Monday.
After a first half lacking in clear-cut chances, Oxlade-Chamberlain brought the game to life by guiding an effort past Julian Speroni following a superb ball by Santi Cazorla two minutes after the break.
|VIEW FROM THE EMIRATES STADIUM
|By Greg Stobart
Arsenal are back at the top of the Premier League - but this win was not as routine as the scoreline might suggest.
Against a well-organised Palace side who packed men behind the ball, the Gunners needed two moments of individual quality from Alex Oxlade-Chamberlain to secure the points.
Oxlade-Chamberlain was making his first start since the opening day of the season, and Arsenal will need him fit and on form as they approach a daunting run of fixtures with a squad depleted by injuries.
Arsenal lacked the ideas and the spark to break down Palace for much of the game but they dominated possession against the visitors, whose gameplan was ruined as soon as the Gunners broke the deadlock.
Palace did show signs of their attacking threat - Cameron Jerome missed one glorious chance - and on this evidence they have a real chance of surviving this season under Tony Pulis.
Oxlade-Chamberlain was recalled in place of the suspended Mathieu Flamini in midfield, but there was no Kim Kallstrom for Arsenal amid reports that the new loan signing has suffered a back injury that could keep him out for several weeks.
Marouane Chamakh started against his former club for Palace.
Unsurprisingly, Arsenal controlled possession in the opening exchanges and their early dominance resulted in the first opening on seven minutes when Nacho Monreal received Mesut Ozil's superb switch of play, and he forced goalkeeper Speroni into action from a tight angle.
Tony Pulis' side settled into the game, however, with Chamakh looking particularly threatening, but a lack of composure in the final third proved costly.
The visitors did need Speroni to be on his guard shortly after the half-hour mark when Ozil's crossed free-kick deceived everybody in the penalty area and forced a smart save.
That proved to be the closest Arsenal went in the first half, with a resolute Palace defence frustrating the home side.
However, it took Arsenal just two minutes to break Palace's resistance in the second half.
Cazorla picked out Oxlade-Chamberlain with a wonderfully clipped pass and the England international controlled well before lofting his effort over Speroni.
Shortly afterwards, Palace missed a gilt-edged opportunity to level the scores. Dwight Gayle's cross deflected to Yannick Bolasie, who in turn nodded the ball into the path of the unmarked Cameron Jerome, but his header was kept out by a fine stop from Wojciech Szczesny.
That miss proved costly for the visitors after 73 minutes. Oxlade-Chamberlain played a swift one-two with Olivier Giroud before driving into the box and drilling his shot past Speroni.
Arsenal rarely looked troubled in the closing stages, with Palace's fight long since extinguished, as the visitors fell to a 15th league defeat of the season to remain just outside the relegation zone.