Jagoba Arrasate's men were beaten comfortably by Villarreal on Monday, while the visitors finally grabbed their first home victory of the season last time out, with a 1-0 win over Real Valladolid.
Match preview
After a strong start to the season, the wheels have been starting to come off for Osasuna over the last few weeks, with three defeats and a draw in their last four games undoing much of their positive early-season work.
Even though their winless run has included an impressive 1-1 draw at the Santiago Bernabeu, home defeats to Getafe and Valencia were particularly disappointing for Los Rojillos, given their 100% at El Sadar before those fixtures.
The Basque side were organised and well-drilled at Villarreal, as is to be expected under Arrasate, but were lacking incision going forward, as they fell to a 2-0 defeat.
Only able to convert their 14 shots on goal into 0.33 expected goals, their trip to the Ciutat de Valencia yielded their least effective attacking performance of the season.
Returning to Pamplona on Thursday, however, against a side who have shown defensive deficiencies so far this campaign, Osasuna will be looking to start aggressively, and to draw on their vociferous home support to see them over the line.
Visitors Espanyol claimed a mightily important victory over Real Valladolid on Sunday, as the unstoppable Joselu netted his seventh goal in just nine appearances for his new side.
Rising highest to power home a lofted cross from Brian Olivan, the former Newcastle United striker sealed a second win of the season for Diego Martinez's men, as the Catalan club won at home in LaLiga for the first time since April.
Perhaps more pleasing for Los Pericos was a long-overdue clean sheet, only their second shutout of the season, following a series of calamitous goalkeeping mistakes that have seen the club become the third-leakiest defence in LaLiga.
With their tails up from an important victory, and with a striker in the form of his life, Espanyol should cause problems for Osasuna, but will be under no illusions about the stern examination that a trip to El Sadar will provide.
Osasuna La Liga form:
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W
L
D
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L
Espanyol La Liga form:
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L
L
D
D
W
Team News
For the hosts, Unai Garcia will return to the centre of defence after serving a one-game suspension, while Ruben Pena will be unavailable due to a longer, three-game ban.
Coach Arrasate will be left with a few selection headaches heading into this clash, with Aimar Oroz, Abde Ezzalzouli and Ante Budimir all vying for starts.
Espanyol are able to welcome back Martin Braithwaite after his three-game suspension, after two goals and an assist in his opening four appearances for the club.
Adria Pedrosa is likely to miss out once again, while Benjamin Lecomte should continue between the sticks after a first clean sheet for the club.
Osasuna possible starting lineup:
Herrera; Cruz, D. Garcia, U. Garcia, Vidal; Torro, Oroz, Moncayola; Abde, Budimir, Avila
Espanyol possible starting lineup:
Lecomte; Olivan, Cabrera, Calero, Gil; Darder, Souza, Exposito; Puado, Joselu, Braithwaite
We say: Osasuna 2-1 Espanyol
Osasuna are in desperate need of a win here, and can count on their passionate home support to make El Sadar a cauldron ahead of the visit of Espanyol.
While we fancy the away side to score due to the red-hot form of Joselu, we are predicting a much-needed victory for the hosts.