Yet he showed no urgency to put the rebound into the net.
First Delap raised his arm to celebrate, then appealed to the officials, before collecting the loose ball and having a shot blocked by the recovering Phillips.
Premier League record goalscorer Alan Shearer, speaking on BBC One during commentary of the game, said: “Goodness me. What is Delap doing?
“It is as if he is thinking, ‘I have all the time in the world’. He ambles to it and he takes his time. What are you waiting for?
“Liam Delap has not had a good four minutes. He has given it away twice and missed a sitter. Delap has been poor and he has been given the opportunity tonight. Delap looks very lazy, his performances have to improve.”
Delap, though, recovered impressively from the error to finish the match with three assists as Pedro Neto’s hat-trick and an Estevao Willian strike sent eight-time FA Cup winners Chelsea into round five.
And he was able to joke about the bizarre moment afterwards as he told BBC One: “I swear on my life I almost ran off [the pitch].
“I thought it went in and then I was waiting for the ref to blow his whistle. Obviously, I should have waited for the ref to blow his whistle. It’s silly from me but yeah, crazy.”
The former Manchester City striker has started just two of Chelsea’s last nine Premier League games, but was handed a chance by Liam Rosenior, with in-form forward Joao Pedro dropping to the bench.
And despite Delap’s misjudgement, the Blues boss praised the forward for his response and part in the success.
The ball he played to Neto for the opening goal in the 40th minute was the first pass he had completed in the final third, having lost possession eight times beforehand.
His second assist for Estevao came after some brilliant hold-up play, while he teed up Neto for the second time at the MKM Stadium with a powerful drive into the box.
Rosenior called Delap’s performance “top” and said: “To be a number nine, especially in a system that we play, it’s not always about yourself.
“It’s about bringing other people into play. It’s about sometimes making sacrifice runs so other players get the space.”
And former Blackburn and Newcastle striker Shearer added: “Delap recovered well from that start and has been instrumental in the win. He deserves a lot of credit for that.”
Ex-Manchester City defender Micah Richards hopes Delap can now “replicate that in the Premier League”.
“I think Liam Delap’s game was brilliant,” he told BBC One. “What I liked about it, is when Hull set up in this five, Delap was thinking if he could get into the space.”
While Delap must wait for his next goal, former Spurs and Manchester City midfielder Michael Brown added on BBC Radio 5 Live: “Delap can do anything. He is like a throwback and is that all-around number nine.
“He is very effective when he is on his game. He is good in the air, he can hold the ball up well, he can defend and he can finish.
“I think he is another outlet. Chelsea now have a plan B if they want to use it and that could be an option.”