The duo made their debuts in Chivas' 2-0 win over Toronto FC on Saturday, prompting praise from head coach Preki.
"We have a couple of new guys and it's not always easy to gel right away with your teammates," said Preki.
"But I thought both of those guys, the longer the game went, they settled in and played better."
22-year old Padilla, who signed on loan from Mexican club CD Guadalajara, said he was very wary on debut.
"[It was my] first game out. I had to see how they play and get used to it and had to relax a little," said Padilla.
Preki went on to praise the forward and had big plans for his new signing.
"He's been here for three or four days and he's been trying to settle down," said Preki.
"He's a young player who hasn't played a lot of minutes, but he has good offensive instincts and we can only hope that he can get better."
Brazilian striker Santos also received praise from Preki after his hour-long shift on debut.
"He's a target guy," added Preki.
"He can hold the ball and he's good with his feet. Now the thing for him is to settle in this league and learn about the physicality of this league. If he can do that, I think he'll be an important player here."