Matt Walker said there are too many Kent players not performing with the bat.
The Spitfires lost their second straight match of the Royal London One-Day Cup against Middlesex at Radlett on Sunday.
It leaves Kent second from bottom of the South Group along with Glamorgan who have also lost both their opening games and above Surrey who play their second match on Monday evening.
Head coach Matt Walker said: “There has been glimpses individually of where we want to be but not as a collective unfortunately.
“You have to play well as a team in these games you can’t rely on one or two people to see you home, especially when you are chasing a score like today, which I didn’t think was out of reach at all at the halfway stage.”
Paul Stirling hit 125 as Middlesex reached 313-9 off their 50 overs. Kent’s bowlers pulled it back in the last 15 overs with the home side 240-2 but struggled towards the end.
Matt Henry (3-60) and Calum Haggett (3-59) were the pick of the Spitfire bowlers.
Walker said: “I think we did pretty well in the first half. It started off not brilliantly but I think Paul Stirling played a brilliant innings in the way he can take a game from you. We responded well and clawed it back nicely in those middle overs.
“Calum Haggett bowled really well and got us back in the hunt. I thought it was a little bit over par.”
Heino Kuhn anchored Kent’s innings hitting 90 batting at four but consistent wickets throughout led to them falling 70 short.
Daniel Bell-Drummond (44), Adam Rouse (34) and Haggett (31) also made contributions with the bat but no-one could go on with Kuhn to put on a match-winning partnership.
Tom Helm was the pick of the Middlesex bowlers on 4-49.
Walker said: “With the bat we are not adding enough contributions through the order. One or two are doing things, Heino today and Daniel a little bit today and against Sussex.
“You can’t rely on one person to get you home. Unfortunately there are too many players not quite delivering with the bat.
“It’s leaving us short of runs and there’s plenty to work on from that front but I don’t think we are a million miles away. I think there are some signs that we are starting to find our feet but this competition is a quick one.”