Irish's flying start to the second half put Newcastle Falcons on the back foot during Sunday's 20-15 defeat at the Madejski Stadium.
Alex Lewington and Topsy Ojo scored the Exiles' two tries within five minutes of the resumption, Newcastle battling back for a losing bonus point through Nili Latu and Marcus Watson's tries, and the boot of replacement fly-half Andy Goode.
Richards said: “The first kick-off threw us after half-time, and to concede the second try in such a sloppy way so quickly afterwards was bitterly disappointing."
“It has been the story of the season so far, and London Irish didn't look like scoring other than on those two occasions. That was the disappointing thing, because we created four opportunities which we didn't convert.”
The director of rugby added: “I feel sorry for our attack coach Dave Walder in many ways, when you look at the guys we have out injured.
“Our backs are firing but not as well as they could be doing, and we lacked that little bit of X-factor. You get that with the likes of Sinoti Sinoti, Alesana Tuilagi, Mike Delany, Tane Takulua, Gonzalo Tiesi and Ruki Tipuna. We are without virtually a full international back line, and we are not scoring as many as we want to.”
Chris Harris had a first-half try turned down by the television match official for a knock-on in the act of scoring, not that the director of rugby was complaining about the decision.
Richards said: “That's life. It wasn't given and you move on. We had plenty of opportunities later on in the game, and right at the death if we had stuck to how we said we were going to play we probably would have gone over."
“But we didn't, we went away from that, and again that was a bit disappointing.”
Dropping back down to the bottom of the table, Richards said: “If we weren't creating the opportunities I would be worried, but we are creating them.
“We just need to nail them, and today was disappointing because of the sloppiness at the start of the second half and the fact we didn't convert our pressure into points.”
At least returning to Tyneside with the consolation of a losing bonus point, he added: “All points are important, whether you're at the bottom, looking at Europe or going for the title. Yeah, we will take what we can from the game in terms of the bonus point, but we wanted more."
“I said before that the 10-game period of back-to-back league games after this next European block is going to be make or break for a lot of sides."
“I think a lot of people were looking at this game along the same lines. Beating Bath the week before made a big difference for us, but that 10-game sequence will be the one which makes or breaks the season of teams at the top and the bottom.”