Defoe's team-mate Wayne Rooney reacted angrily to the supporters' reaction, saying to the television cameras as he left the pitch: "It's nice to see your home fans booing you."
Defoe, a second-half substitute, was more philosophical.
"I think it is part and parcel of playing at this level," he said.
"You can understand fans getting frustrated and obviously they have travelled miles to come and support the team. But I think it's important for the fans to stay behind us because the lads are devastated we didn't win tonight.
"We want to do it for everyone back home, for our families, the boys, the manager and everyone.
"It's not nice to get booed, to be honest, especially when you try your best and it's difficult out there."