A 5-0 victory over the minnows at Wembley was a nice tune-up for Roy Hodgson's men ahead of the midweek World Cup qualifier in Warsaw, with strikers Wayne Rooney and Danny Welbeck profiting with a brace apiece.
England are only too aware a trip to the Euro 2012 co-hosts represents a significant step up in calibre, and Everton defender Jagielka is grateful that England's workmanlike performance against San Marino threw up no surprises.
"Three points in the bag, five goals scored and none conceded, as far as we're concerned it was a good professional job done," Jagielka told a press conference.
"We knew what kind of a test we were in for and we got through it okay - is probably about the right word - and we knew that Tuesday is probably going to be a lot more of a test.
"It was all about a clean sheet from the defensive point of view and for the front men to create and score goals and get some confidence heading into Tuesday.
"We're expecting a much more difficult game on Tuesday night."
Frank Lampard (calf) and Ryan Bertrand (illness) have both been ruled out of the game after failing to recover from the problems that also saw them miss out against San Marino.
The Chelsea duo's club team-mate Ashley Cole, meanwhile, finds himself at the centre of Hodgson's biggest selection call for Tuesday night, with Everton's Leighton Baines pushing him hard for the left-back berth.
Baines turned in another impressive performance during the San Marino win and he has now started all four internationals since the Euro 2012 finals as Cole nurses an ankle problem.
The former Wigan man now looks a genuine contender for the number three shirt, and Jagielka admits his Everton team-mate is pushing Cole hard.
"It's going to be a really tough decision," said Jagielka.
"You've got Ashley Cole on 98 caps, and probably the in-form player in the Premier League in Leighton Baines who's playing there at the moment.
"As far as the manager goes it's a headache, but probably a nice one to have.
"I think I'd be flicking a coin."
On the absence of Lampard, Jagielka added that he expected Michael Carrick and Tom Cleverley to again shine if asked to deputise alongside returning captain Steven Gerrard.
"Frank's done well for England, especially recently, so we will be missing him," he said.
"But if you look at the other night's game, Michael and Tom did fantastically well and we've also got our captain to come back, so cover for Frank not being here is looking really good at the moment."