Chelsea interim boss Guus Hiddink insists the FA Cup must still be treasured after his team dumped a much-changed Manchester City side out of the competition.
The FA Cup has come under scrutiny which will only continue after Manuel Pellegrini's selection.
City made nine changes and fielded six teenagers - five of them making their full debuts - in Sunday's 5-1 defeat at Chelsea, who next play Everton in the quarter-finals.
But the Dutchman will not devalue the competition.
"Winning the FA Cup is beautiful. We must be careful not to devalue this," said Hiddink, who won the competition with Chelsea in 2009, beating Everton in the final.
"I had good memories of that time, but that's the past. Some might be still in that team and they go for their revenge.
"They gave us a difficult time here (a 3-3 draw in January). We hope to maintain our FA flow a bit when we play them. Not easy."
With the Blues languishing in 12th place in the Premier League, the FA Cup and Champions League are now Hiddink's priority.
"There's not much left in the league for Chelsea, to be honest," he said.
Just 90 seconds after going behind to Diego Costa's opener, City equalised through David Faupala, one of the five full debutants, and it was 1-1 at half-time before Chelsea's second-half blitz.
Willian and Gary Cahill scored within eight minutes of the restart and Eden Hazard and substitute Bertrand Traore added goals.
Chelsea also had a penalty, but Oscar's effort was saved by Willy Caballero.
Hiddink extended his 100 per cent record in the competition to six games and has now lost just one of 13 games in all competitions since succeeding Jose Mourinho in December.
Chelsea appear in good health, with Cesc Fabregas influential and Hazard performing well in a second successive 5-1 home win following the Premier League defeat of Newcastle.
Hiddink, who described the concession of the equaliser as "sloppy", said: "Of course it's a boost for the confidence of the players. It's good to see that.
Pellegrini insisted Manchester City had no choice but to prioritise the Champions League over the FA Cup following their fifth-round loss at Chelsea.
They play Dynamo Kiev in the Champions League on Wednesday and the Capital One Cup final with Liverpool next Sunday, so the City boss delivered on his promise to make wholesale changes.
"If one team respects all the cups it's this team," said Pellegrini, who denied disrespecting the competition.
"That's why we are in the final of the Capital One Cup, that's why we won the two previous games in this cup. Today we couldn't because I think we have more important things at this moment.
"I think one of the most important things that we must do here in England is to try to help English teams playing (in the) Champions League.
"We cannot take the risk. I have just 13 players (available) at this moment."