Ben Yedder helped his side to a 2-0 win in the Copa del Rey quarter-final first leg, lifting his shirt to reveal a message that read, "For my brother. Strength. E.Sala."
Sala has been missing since the airplane taking him from Nantes to South Wales went missing over the English Channel on Monday evening.
His disappearance came after he had completed a £15 million ($19m) to Cardiff in a club record deal.
En mi corazón y en mis oraciones 🤲🏻❤❤️ Pienso en ti Emi pic.twitter.com/Irn6FvYDxF— Wissam Ben Yedder (@WissBenYedder) January 23, 2019
Although Ben Yedder, a France international, has never played for the same club as Sala, he played against the former Nantes and Bordeaux striker in a number of Ligue 1 clashes when playing for Toulouse.
The search for the 28-year-old and his pilot David Ibbotson - the only two men on board the aircraft - will continue but hopes of finding either of the two men are fading fast.
John Fitzgerald, chief officer of Channel Islands Air Search, indicated to the BBC that "even the most fit person" would last only a few hours in the Channel at this time of year.
"Sadly, I really don't think, personally, there is any hope. At this time of year the conditions out there are pretty horrendous if you are actually in the water," he said.
Cardiff had hoped Sala, who has netted 12 goals in 19 appearances in France's top flight this term, would make a strong impact to help their fight to stay in the Premier League.
And the forward's friend and spokesperson Martin Molteni has said Sala's family still hope to find him: "We only have the information being released by the official media."
"The search continues. We're in constant communication with the Argentine embassy in France, the provincial government and Emiliano's agent.
"All the efforts are in finding the plane. Then, an investigation must be done. Romina, Emiliano's sister, travelled to England with her partner and a companion. She had official help to facilitate her entrance to the UK."
The search for the missing plane is expected to continue on Thursday.