The Blades barely threatened at Kenilworth Road, with the hosts looking by far the more likely team to score in the second period and seeing Fred Onyedinma’s effort disallowed for offside.
Jokanovic, still searching for a first Championship victory of the season, said: “I can’t be satisfied, we didn’t show enough quality.
“We were without enough energy and at the end of the game I did not have the sensation that we were close to winning the game.
“We tried but without the quality and the energy it wasn’t easy for us.
“In general, it has not been a positive start to the season.
“It’s not a question about shape or formation, it’s about how to play football, it’s about intent.
“We changed at half-time because Luton were playing lots of long balls, so we made the decision to play one more offensive player up to make more damage.
“But it didn’t work especially good and, without the basics, it was too complicated to create the positive things and get closer to winning the game.
“A lot of these players have played Premier League football, but you cannot be scared about the game.
“You cannot lose the game before you start. We need personalities.
“We needed to show more, we needed to create more. There is much to work on.”
A quiet first half saw George Baldock head the best chance over for United at the far post.
Luton upped the tempo in the second period, Onyedinma racing through to poke a finish past Wes Foderingham, only to be denied by a raised flag from the referee’s assistant.
Allan Campbell fired into the side-netting and Harry Cornick hit the bar from close range, while James Bree flashed a late attempt narrowly wide.
Town boss Nathan Jones was happy with his side’s display following a 5-0 defeat to Birmingham last weekend.
He said: “I thought we did enough to win the game, but what I’m really pleased with and what shows what we have here is just how we bounced back from last week. We reacted very well, we bounced back.”
Luton Town: Sluga, Bree, Burke, Naismith, Bell, Osho, Mpanzu, Cornick, Campbell (Rea 83), Onyedinma (Muskwe 84), Adebayo. Unused substitutes: Shea, Mendes Gomes, Lockyer, Pereira, Kioso.
Sheffield United: Foderingham, Basham (Freeman 46), Egan, Davies, Baldock (Bogle 31), Berge, Norwood, Fleck, Norrington-Davies, Sharp, McBurnie (Brewster 69). Unused substitutes: Burke, Robinson, Verrips, Osborn.
Referee: Andy Davies (Hampshire).