Manchester City had to wait till injury time to wrap up a two nil win over a Dinamo Zagred team that proved difficult to break down for Guardiola’s men.
First half ended with no goals to either teams but City broke the deadlock in the 66th minute.
Sterling swept home from a Riyad Mahrez cross midway through the second half, then set up 19-year-old Foden in stoppage time as City’s second successive win took them top of Group C.
Guardiola said: “He (Foden) has incredible finishing and made an incredible step forward tonight.
“I am so sorry for him – he deserves to play more minutes. I am sure he will contribute and help us more.”
The England squad for the next round of internationals is named on Thursday.
“I am buzzing for Phil Foden,” Sterling told BT Sport. “I want him in the national team. If he keeps going he will be there.”
Foden said: “You have to show the manager what you can do each day in training. Every young kid wants to play but you have to keep patient.”