While the home side recorded a 2-2 draw with Ajax at the weekend, the visitors were held by mid-table outfit PEC Zwolle.
When his side established a 2-0 advantage at Ajax within the opening quarter of Sunday's match, PSV boss Roger Schmidt would have been confident of retaining hold of that lead for the duration of the contest.
The leaders ultimately fought back to get back on level terms by the 65th minute, inevitably leaving Schmidt with mixed emotions ahead of what could become a four-way chase for the title.
While Feyenoord and Vitesse only are regarded as outsiders, PSV now have to take notice of the teams below them, as well as ensuring that they do not drop any more points in the coming weeks.
PSV head into their meeting with the fifth-placed side having extended their unbeaten streak to 12 games in all competitions, a run which has lasted since November 8.
Despite supplying two assists in Amsterdam, Donyell Malen is under pressure to improve on a return of two goals from his last five appearances.
Although AZ head into this contest having avoided defeat in their last five league encounters, back-to-back draws have not helped their title push.
Pascal Jansen's team now sit seven points adrift of Ajax after failing to overcome mid-table pair FC Utrecht and PEC Zwolle either side of the New Year break.
Nine games have now been played since AZ recorded a clean sheet, but 19 goals have been scored at the other end to keep the club on a positive track.
While they remain with just one defeat in 15 matches in the Eredivisie, Jansen will acknowledge that draws are no longer good enough if the club wish to challenge for Champions League qualification.
Nevertheless, there will be few complaints if they earn a share of the spoils on Wednesday, even if a stalemate puts the club at risk of dropping down to seventh position.
PSV Eindhoven Eredivisie form: WDWWWD
PSV Eindhoven form (all competitions): WWWWWD
AZ Alkmaar Eredivisie form: LWWWDD
AZ Alkmaar form (all competitions): LWWWDD
With three tough fixtures in the space of a week, Schmidt will have to considering making changes for this game.
Jansen has a decision to make regarding Bruno Martins Indi, who came through 60 minutes on his return from injury at the weekend.
Ron Vlaar is back in the squad after a lengthy absence, making the veteran centre-back an option for Jansen if no risks are taken on Martins Indi.
PSV Eindhoven possible starting lineup:
Mvogo; Dumfries, Teze, Boscagli, Max; Rosario, Tangare, Thomas; Junior, Madueke, Malen
AZ Alkmaar possible starting lineup:
Bizot; Sugawara, Hatzidiakos, Martins Indi, Wijndal; Midtsjo, Reijnders, Koopmeiners; Stengs, Boadu, Karlsson
We say: PSV Eindhoven 3-1 AZ Alkmaar
Despite the possibility of lingering frustration within the PSV ranks, we feel that it could play into their favour for this contest. AZ are capable of recording a surprise win, but the home side should have enough quality in the final third to outclass their opponents.