Alejandro Rego's late winner sees us fall to a 2-1 defeat to Athletic Bilbao in San Mamés after Samu Costa's second-half strike cancelled out Iñaki Williams's early penalty.
Jagoba Arrasate opted for continuing with Marc Domenech at right wing while Vedat Muriqi led the front line as the lone centre forward.
Dani Vivian, Iñaki Williams had Robert Navarro early chances for the hosts who started the better side and kept Leo Roman busy.
Iñaki Williams gave the hosts the lead from the penalty spot in the ninth minute after a VAR review adjudged Martin Valjent to have fouled the winger who made no mistake from 12 yards.
Despite the flurry of chances in the opening exchanges, the game was subdued by the goal and we headed into the break with little sight of finding a way back into the game come the break.
Mateo Joseph and Javi Llabrés were introduced to add a bit more flair in the final third after the restart as we looked improved in the second half.
This would eventually lead to our equaliser in the 77th minute when Samu Costa registered a contender for goal of the season with a looping effort from distance close to the byline.
Our efforts were to go unrewarded however as Rego restored Athletic Bilbao's lead five minutes later when he latched onto Jesus Areso's low ball and found the bottom corner.
LINE-UPS:
RCD Mallorca: Leo Román, Muriqi, Morlanes (Antonio Sánchez, 83'), Segi Darder, Samu Costa, Pablo Torre (Mateo Joseph, 66'), Raillo, Johan Mojica (Morey, 88'), Maffeo (Lato, 88'), Valjent, Domenech (Llabrés, 66')
Athletic Club: Unai Simón, Vivian, Iñaki Williams (Nico Williams, 53'), Guruzeta (Rego, 62'), Areso, Laporte, R. De Galarreta (Leuke, 82'), Yuri, Jaureguizar, Nico Serrano (Sannadi, 62'), Navarro (Izeta, 82')
Goals: Iñaki Williams (0-1, 9', penalti); Samu Costa (1-1, 77'), Alejandro Rego (2-1, 82')
