The Emirates Stadium outfit's run in Europe's elite club competition looked set to come an end when they suffered a 3-0 defeat at the hands of Everton, their main challengers for fourth place, last month.
However, two major slip-ups from Roberto Martinez's men since then have put Arsenal firmly back in the driving seat for Champions League qualification.
Everton have lost to both Crystal Palace and Southampton in recent weeks, while Arsene Wenger's side have bounced back from their Goodison Park loss with three straight Premier League wins - scoring nine goals in the process.
However, Arsenal, now four points clear of Everton, have met West Brom on two occasions this season - once in the League Cup and once in the league - and have been held to 1-1 draws after 90 minutes in both matches.
A weakened Arsenal eventually edged through on penalties in the cup tie, and this will be the first Emirates meeting between the clubs since Mikel Arteta scored twice from the spot in a 2-0 Arsenal win in December 2012.
Wenger's team have only lost two home Premier League games since that clash 17 months ago, but the Frenchman has bemoaned the number of fixtures his side have drawn at the Emirates this season.
"The restriction we had was in the big games, when we only made draws and not wins in some of them," he said. "That's where the missing points are at the moment because we are very close to the top.
"Maybe one or two wins at home would have made that difference.
"The regret we have of the season is that we have been remarkably consistent, (but) it is against the teams who did not fight for the Premier League title."
West Brom's win over West Ham last week lifted them four points clear of the relegation zone, so an unlikely victory on Sunday would be enough to ensure their survival.
Head coach Pepe Mel insists his side are still not safe, but if Cardiff City and Fulham fail to win and Norwich City lose this weekend, West Brom's top-flight status will be assured for another season, regardless of their own result.
Jack Wilshere (foot), Alex Oxlade-Chamberlain (groin) and Kieran Gibbs (hamstring) remain sidelined for Arsenal, while Bacary Sagna is a doubt with a knee injury.
Gareth McAuley (calf) could be in line for a return for West Brom, while Steven Reid (groin) and Zoltan Gera (hamstring) are set to miss out.
