Walker says Man City must use Champions League pain to fuel FA Cup and league title chases
Last season's treble winners suffered a 4-3 penalty shootout loss to Real Madrid in their Champions League quarter-final at Etihad Stadium on Wednesday.
Pep Guardiola's side are two points ahead of Arsenal and Liverpool in the league with six games remaining and play Chelsea in the FA Cup semi-finals on Saturday.
"It hurts and we've got to feel the pain," Walker told reporters.
"We've got a massive run-in for the Premier League, a really big game against Chelsea and we have to take this as motivation to go on and do something special.
"It is a great opportunity to take this hurt and fire from our belly ... We owe it to the fans and as a group of players we've worked too hard to throw it away now."