Arsenal took one step towards saving their season with victory over Wigan Athletic in the FA Cup semi-finals on Saturday, but they still have a lot of work to do to ensure that 2013-14 is not a disappointment.
While the Gunners were scraping past Wigan via a penalty shootout at Wembley, Everton were celebrating their new position in the Champions League qualifying places, having displaced Arsene Wenger's side earlier that day.
Wenger will be as desperate as anyone to end the nine-year trophy drought that looms over the club, but he will also be fully aware of how important Champions League football is for the Gunners. In many ways, Tuesday's match against the Hammers is as important as Saturday's semi-final against Wigan.
However, any return to the top four on Tuesday could only be for 24 hours as Everton play their game in hand against Crystal Palace on Wednesday night. Champions League football is out of Arsenal's control, but they need to be ready to pounce upon any slip-ups on Merseyside.
Questions must be raised over how much Saturday's semi-final took out of the Arsenal players, however. A gruelling 120 minutes on the notoriously energy-sapping Wembley surface is not the ideal preparation for a match just three days later, particularly for a side as depleted by injuries as Arsenal.
There is also the lingering issue of the Gunners' recent form. While the euphoria of reaching the FA Cup final was understandable, the reality is that they struggled to find a way past Championship opposition and have not won a game inside 90 minutes for almost a month.
Just two points from their last four league games has left them in a tricky position, but they have not failed to win five Premier League games in a row since 2009.
Back-to-back draws against Swansea City and Manchester City at the Emirates mean that they have not won a league game in front of their own fans since February 22, but they are unbeaten at home in the league since the opening day of the season.
With two games in such quick succession, Wenger is expected to make changes to his team for Tuesday's match. Olivier Giroud could return in place of Yaya Sanogo and Wojciech Szczesny is likely to come back in goal in place of FA Cup hero Lukas Fabianski.
In contrast to the Gunners, West Ham have had nine days to prepare for this match and will go into it fresh and full of confidence having tested league leaders Liverpool in their last outing.
The Hammers looked to be among the favourites for the drop at one point, but Sam Allardyce has turned things around for the club and they are now just three points away from the magical 40-point mark.
In truth, their currently tally of 37 should be enough to keep them clear of the bottom three, although wins for Fulham and Cardiff City at the weekend will have had Allardyce glancing over his shoulder once again.
Six wins in their last 10 matches is certainly not relegation form, but they have struggled against the bigger teams this season, only picking up one victory against sides in the top seven of the table.
They have been fairly solid on their travels, however, winning three and losing just two of their last six away games, with the sole draw an impressive one at Stamford Bridge.
Speaking of Chelsea, only the Blues have kept more clean sheets than the Hammers this season, but Allardyce does have defensive issues to deal with as James Collins, George McCartney and Joey O'Brien are all doubts.
West Ham: LLLWWL
Possible starting lineups
Arsenal: Szczesny; Sagna, Mertesacker, Vermaelen, Gibbs; Arteta, Ramsey, Cazorla, Oxlade-Chamberlain, Podolski; Giroud
West Ham: Adrian; Demel, Tomkins, Reid, Armero; Downing, Noble, Taylor, Diame; Nolan, Carroll
Sports Mole says: 2-0