Leyton Orient head coach Richie Wellens said his side need to improve after falling to a 1-0 defeat at League One strugglers Fleetwood Town.
O's made a bright start at Highbury Stadium, but could not make their dominance count as the scoreline remained blank.
And they were punished on 56 minutes as Jack Marriott claimed the only goal of the game to give the hosts their first win in nine outings this season.
"We've wasted three points," Wellens told the club website.
"First half an hour, totally dominant, the atmosphere was really quiet, they're obviously struggling, and we had an opportunity to be ruthless and we should be one or two up.
"Fair play to them, they stuck in there and turned the game around, with probably 10 minutes to go in the first half, and then we started the second half really poorly, they got the crowd involved.
"The amount of good situations we got in first half, we've got to score.
"If you don't you always run the risk of the opposition coming into it.
"Fair play to them, they just run a little bit, won second balls, a few duels, and that's probably won them the game."
O's made a tactical switch in swapping Theo Archibald and Jordan Graham and Wellens felt it worked well, but was just lacking the end product.
"Theo had the ball six or seven occasions in the first half and got one shot off but probably could get more shots off. The same with Jordan Graham," he added.
"We think that tactical switch worked, in terms of the positions they got into but we've just got to be better, we've got to take shots on, we turned too many shots down.
"We need to be more ruthless, attack quicker, make decisions quicker, and if we do that we probably win the game."
Wellens, with more players at his disposal after injuries, again used five substitutes, but the first three had not been on the pitch long when Marriott netted.
"I think they looked threatening, Driz [Aaron Drinan] probably should shoot instead of rolling Ruel [Sotiriou] on, and Theo has put five wonderful balls in the last 15 minutes, with two strikers and a 10 getting in there," he said.
"We've got a big squad and I want to keep everybody happy. I've contemplated making changes, even though we've won the last game. We need to improve."
O's were cheered on by around 300 travelling supporters and Wellens admitted his players should have given them more to cheer after a tricky journey to the north west.
"With the train strike, the weather's not great, they made a lot of noise, we just needed to do better to allow them to go home with three points," he added
"We need to be brighter. People need to look at themselves in the mirror and say 'Can I do more? Can I work angles better? Can I play forward better or more often?'
"There's still a little bit of petulance about us at times, which I want us to improve upon.
"The performance was ok, dominant the first half an hour, but I watched their last home game here - Oxford are a good side, really good League One team, and they dominated for the first half an hour, scored a goal, twist that knife and they're ruthless.
"We just squandered too many chances and too many opportunities to make even more chances. We got done with one counter-attack."
O's return to Brisbane Road to host Lincoln City on Tuesday, before Reading visit next weekend.
And Wellens wants them to make home advantage count, adding: "Lincoln are an established League One team. Under Michael Appleton they finished in the play-offs, then the last few years under Mark Kennedy they've been around mid-table.
"They're a good, solid League One outfit, don't concede many goals.
"I'm hoping for a good crowd because we've got £10 a ticket, we need to make full use of these next two homes games.
"I do think in the next 10 games the league will really start to take shape. I still think it's a little bit squashed at the moment. We've wasted three points today."
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