Fulham paid Leeds £11m for the Scotland international - a record fee for a Championship club - but he could not get on the scoresheet against one of his former clubs.
Goals from Cameron Burgess and Kostas Stafylidis ensured Felix Magath's men finished their tour unbeaten against the Scottish Premiership runners-up, who begin their Europa League qualifying campaign next week.
"Overall, today I was very happy, it was a very good performance," Magath told Sky Sports News. "I was a little bit surprised as we worked very hard last week so I was not expecting the team to play so well today.
"Everyone has seen what a good player Ross McCormack is, but at the moment he is not in his best shape. He played 90 minutes but he has only been with us three days. But I am very glad to have him on board. There will be two or three more players that we need. We have a very good spirit and everyone likes to work hard and everyone is glad to be here."
Burgess opened the scoring with a thumping header from Chris David's corner and Fulham continued to hold the upper hand as Kay Voser, Lasse Vigen Christensen and David all went close before the break.
After a flurry of substitutions, McCormack found himself wearing the captain's armband with the departure of Scott Parker and Stafylidis (56) - who has joined on loan from Bayer Leverkusen - saw his shot from 22 yards slip through the grasp of Dan Twardzik in the home goal.
Motherwell did have their moments, with Bob McHugh working Marcus Bettinelli and John Sutton blazing over when well placed.
In the final quarter, McCormack and George Williams both tested the Motherwell goalkeeper as Fulham ended the game as they had begun, in the ascendancy.