Wigan Athletic boss reacts to Sunderland setback
Charlie Wyke's 44th-minute goal gave the visitors a half-time lead at the Stadium of Light.
But the home side came roaring back into it after the break, and goals from Elliot Embleton and Dennis Cirkin gave them a victory they merited overall
"I'd start by giving credit to Sunderland for the result," acknowledged Richardson.
"I thought we were worthy of the lead at half-time, we were very competitive and very good in and out of possession.
"In the second half, we didn't quite deal with that 15-20 minute spell they had.
"And their goals are disappointing...one of them's from our goal and the other's from a quick free-kick.
"But fair play to them, they have some very good players, and very good players in one-v-ones.
"You have to manage those moments and those situations better, though, and we're disappointed we weren't able to do that."
Richardson recognised the game-plan had worked a treat for 45 minutes, before it all went wrong in the second period.
"I thought we always looked dangerous on the counter, our distances were very good," the Latics boss added.
"I just thought in the second half we possibly played the result a little bit.
"For 15-20 minutes we were maybe five yards too deep, and our distances weren't as good.
"And overall, we were nowhere near as good as we were in the first half.
"But in the closing stages, when they maybe started to play the result a little, we had a few half-chances."
The first half was really scrappy with neither side able to get anything going due to the referee's whistle.
Sunderland thought they'd scored, but the flag was long up for offside and the 'goal' was chalked out.
The only other incident of note came when Embleton went in late on Wyke, and was perhaps fortunate to receive only a yellow card from Keith Stroud.
Wyke, however, administered his own justice a minute before the break when he silenced the home supporters who once idolised him.
Indeed, ex-Sunderland men Nathan Broadhead and James McClean were also involved, with the Irishman's cross being finished off superbly by Wyke at the far post.
Up to that point, the hosts had enjoyed much of the all and created a few half chances, but Ben Amos hadn't had any real cause for concern in the away goal.
That all changed within nine minutes of the restart, when Embleton - of all people - finished off Dennis Cirkin's cross.
And Cirkin it was who put Sunderland ahead with 18 minutes to go, from Patrick Roberts' inviting delivery.
Thelo Aasgaard, Ashley Fletcher and Graeme Shinnie took over from Tom Naylor, Broadhead and Curtis Tilt for the last 15 minutes.
But the closest Latics came was from a McClean corner, with top scorer Will Keane unable to hit the target with a close-range header.