The Shrimpers suffered a 1-0 defeat at the J Davidson Stadium on Saturday.
READ MORE: Blues fans have their say on defeat to Altrincham
And Coker was frustrated Blues could not make more of their possession.
“It’s a tough one to take,” said Coker.
“The second half was more like us but I thought we started a bit slow in the first half.
“They were sitting in and we couldn’t really break them down too much.
“We still had chances and in the second half I thought we were all over them.
“We dominated but I think in the final third we were a bit rushed at times.
“We were snatching at shots maybe but it’s one of those days.
“We’ve had 21 shots and attempts at goal and it just didn’t go our way.”
Altrincham bagged what proved to be the only goal of the game after just 14 minutes with Liam Humbles hitting the back of the net after Blues failed to deal with a corner.
And Coker was disappointed with his own part in the goal.
“We’ve been good from corners but we didn’t win the first one and I was ball-watching on the edge of the box so my man scored,” said the midfielder.
“We reacted quite well and it was all us really.
“We had all of the ball but overall we need to be more calm in the final third and get cleaner shots away.”
The defeat saw the Shrimpers slip to eighth in the National League standings.
And Coker was annoyed not to be able to make it three wins in a row.
“It’s frustrating,” said the 23-year-old.
“The last two games we’ve shown the levels we can produce.
“I don’t think we were bad on Saturday.
“We created so many chances and had all of the ball.
“But we know we should be beating teams like this with the chances we had.”
The Shrimpers will now be looking to get back to winning ways when they host Woking at Roots Hall tomorrow night.
And Coker is pleased to have a quick opportunity to respond.
“We can put it right on Wednesday and the games are coming thick and fast now which is good for us off a result like this,” said Coker.
“We need to keep pushing, keep on doing the right things and things that we know work then things will come our way.
“We need to keep on doing what we’re doing.
“Against Forest Green and Rochdale we played really well, did the right things and put the ball in the right area.
“We did the same again on Saturday, but in the final third it just didn’t go our way.”