The neutrals watching on television were all hoping to see King’s Lynn cause an Emirates FA Cup upset.
Pompey, meanwhile, were expected to beat their non-league opponents at Fratton Park and the pressure was all on them.
But the hosts produced a professional performance to ease to a 6-1 victory in round two, with Rasmus Nicolaisen scoring after just 108 seconds.
Tom Naylor and Jordy Hiwula both found the target with stunning strikes, while Sean Raggett, Marcus Harness and Ellis Harrison – from the penalty spot – also got in on the act.
Kenny Jackett was delighted with the display and hopes that Monday evening’s draw will be kind on his side.
The Blues boss said: “I’m very pleased to get through in the third round after a tough tie at Ipswich and a potential banana skin against King’s Lynn.
“We managed to get a good goal in the opening moments, but then they had a couple of chances soon after that.
"You want a Premier League team if you get to the third round and it’s always a big thing – home or away."
“In the end, though, we scored with some excellent strikes and I really enjoyed watching us play in the second half.
“Tom’s making a habit of those goals from the edge of the box and we’re happy with that because it was probably the key one for us.
“We see Jordy in training and he’s more suited to the front two than out wide, but he can cause problems with his pace and has been patient.
“You want a Premier League team if you get to the third round and it’s always a big thing – home or away.”
Jackett had made five changes to his starting line-up, with a long trek to Blackpool lying in wait on Tuesday.
He said: “There’s been a big volume of games and it’s the same coming up, but we still fielded a team who have played a lot of football.
“We had some like-for-like replacements and I was comfortable with that because we needed some fresh energy.
“Ben Close picked up a bit of cramp towards the end, but it doesn’t look anything serious and that’s good news.”