Gresini team boss Fausto Gresini described Friday practice without the late Marco Simoncelli as "surreal" as his squad returned to MotoGP action at Valencia two weeks after the Italian's death in Malaysia.
The satellite Honda team is running a single MotoGP bike for Hiroshi Aoyama this weekend, plus Michele Pirro and Yuki Takahashi in Moto2. Simoncelli's #58 bike is on display in the garage.
"There is so much sadness in our garage today," said Gresini. "The atmosphere was surreal without 'Super Sic' there and it has been extremely difficult to tackle the day.
"It goes without saying that he is missed but it was important for us to be here and honor his memory because I am sure this is what he would want. Hiroshi tried to find the limit in difficult conditions but it was tough for him. I am sure he will give his best on Sunday in Marco's name."
Aoyama was 14th quickest in the morning and 15th in practice two, when he had a late crash. The Japanese rider is making his final MotoGP appearance this weekend before leaving for a Ten Kate Honda World Superbike ride.
"The conditions made life hard today and I had a crash," he said. "The grip levels weren't the best and even though I tried to find the limit it was very hard and I am not happy with the result. I hope I can be faster tomorrow and on Sunday.
"This is an important grand prix for me because it is my last in MotoGP and I am desperate to have a good race to honour Marco, who we are all missing greatly. I will try to do my best for all these reasons."