But as the hosts upped the pressure they got a fortuitous equaliser as Massimo Luongo's backheel from a corner was diverted past Argyle keeper Michael Cooper by team-mate Bali Mumba.

Town went ahead when George Hirst calmly finished after an error by Dan Scarr before Marcus Harness made it 3-1, coming after the visitors went down to 10 men due to Bundu going off injured with no substitution windows remaining for the Pilgrims.

Argyle skipper Joe Edwards converted a Mumba cutback from the byeline in stoppage time to set up a nervy finish, but Ipswich held on.

The win extended Ipswich's unbeaten run to 11 games in all competitions while Argyle slip to 19th place.

The hosts should have gone ahead in the third minute when Hirst was put through by Conor Chaplin's dink over the top, but his weak effort trickled past Cooper - allowing the Argyle goalkeeper time to recover and dive on the ball just as it was about to cross the line.

Whittaker's goal came when he cut in from the right before caressing an effort into the left corner past the diving arm of Vaclav Hladky.

Whittaker had a weaker effort from a similar angle saved soon after before Argyle's leading scorer going into the game, Ryan Hardie, was forced off with what appeared to be a right hamstring injury.

The game's moment of controversy came after 42 minutes as Hardie's replacement Bundu broke clear and was brought down by Edmundson on the edge of the box. Referee Gavin Ward felt he played the ball but replays showed he did not, although it was debatable whether contact was made inside or outside the box.

Hutchinson and Nathan Broadhead went close soon after before Mumba's own goal levelled it at the break, and Town were ahead when Scarr failed to deal with Leif Davis' ball down the left and Hirst made no mistake from 12 yards out.

Town should have been 3-1 up five minutes later when Kaine Kesler-Hayden deflected Hutchinson's effort wide after good work by Davis.

Ipswich had Hladky to thank as they kept their lead - first he was smartly off his line to clear as Finn Azaz almost meet a cross, then he palmed away a Scarr back-post header from a corner before superbly denying Edwards with his feet as the Argyle skipper went clean through after Bundu's shot was blocked.

The Pilgrims' day got worse as Bundu was forced off with a hamstring problem, with no ability to make a change, and the extra space allowed Leif Davis the time to put in a cross for Harness to convert at the second attempt after his first effort was blocked.

But Edwards' goal made stoppage time tense, even more so when Ben Waine had an even later effort saved.

Ipswich Town manager Kieran McKenna told BBC Radio Suffolk:

"I think both teams showed why they had such good seasons last season, why we both performed so well in League One.

"There were some real quality goals scored and both teams fighting for the result, so a hard-fought game, I didn't expect anything less really.

"It was always going to be hard-fought, and it proved that way, and I'm happy to come out on top."

Plymouth Argyle manager Steven Schumacher told BBC Radio Devon:

"The lads played unbelievably well, I've just said to them I'm proud of them.

"The efforts they put in, the way that we stuck to the plan today - we knew these have been the best team in the league with Leicester.

"We knew we were going to have spells where we stuck together and defended, because it's hard to stop them, but I felt we did that in the first half.

"We defended really well and counter-attacked with a purpose - our goal was outstanding from an interception.

"So I was really pleased with how the whole of the half was going, and I'm obviously fuming over how we didn't get a free-kick right on the edge of their box at a really pivotal moment in the game."