Saddlers started well and played some nice football, but failed to properly test the Shrimps’ goalkeeper.
Then, a Dan Scarr mistake allowed the visitors to take the lead before they cruised to victory in the second half – and Kinsella believes the failures in both boxes were to blame.
He said: “We were brilliant first half. We controlled the game and played some really good football.
“If you want to be picky, the final pass in the final third let us down a little bit.
“It was a positive and good performance and it’s just frustrating we didn’t come away with anything.
“It’s just a mistake. It changes the game as they’re 1-0 up and want to hold onto that lead.
“We had to try and break them down. We have to be more ruthless in both boxes. Keep concentration when defending and when going forward make that final pass.
“Once they got the goal they defended very well and we couldn’t break them down how we’d like.
“It’s a very frustrating day at the office.”
When asked if you can coach errors out of players, head coach Brian Dutton added: “It’s very difficult.
“It’s pretty basic defending. Sort your body positioning out and clear the ball but we didn’t do that.
“You could spend time on the coaching field telling these guys how to do it but it would be quite patronising. It’s stuff that you’d feel red-faced talking to the academy boys about.
“It’s the basics and they know better. You can coach it I suppose but you shouldn’t need to, they’re professional footballers at League Two level.
“They’re human beings and we all make mistakes and hopefully we can learn from it.”
Throughout the game Walsall proved toothless in front of goal, highlighting a major issue they have had since Elijah Adebayo was sold to Luton in January.
For Dutton, that sale and the failure to replace him, was a crucial mistake.
He added: “If you let go a Championship striker who has scored a third of your goals you need other guys to step up to the mark or you need to replace him with someone proven.
“We haven’t done that and that’s why we’re in the position we are.”