Luton's Allan Campbell could not hit the target from a tight angle
Sheffield United boss Slavisa Jokanovic has called for the board to "refresh the squad" after his side's wait for a first Championship win of the season went on as they laboured to a goalless draw at Luton.
The Blades have picked up just two points from their opening five league games following their relegation from the Premier League, scoring only once.
"The board must do what they promised me before I came here and refresh the squad - this is simple, I cannot explain it in a different way," Jokanovic told BBC Radio Sheffield.
"They must do it. This is the deal, it's between serious people - I am confident they will do it."
United started brightly at Kenilworth Road - George Baldock nodding over when unmarked at the back post - but the half soon fizzled out, Elijah Adebayo heading off-target as Luton came into the game.
Nathan Jones' Hatters dominated after the break, Allan Campbell shooting into the side-netting before Fred Onyedinma had a goal disallowed for offside.
And they came even closer when visiting keeper Wes Foderingham was tackled in his box and Harry Cornick could only hit the underside of the bar, with James Bree curling just wide late on.
The Blades go into the two-week international break in 23rd, above only Nottingham Forest, with the transfer window closing on Tuesday.
"These three days will be an important three days for our board, to do what they promised before I arrived here," added Serbian Jokanovic, who has won promotion from the Championship previously with Watford and Fulham.
"It's not a question about today, it's a question about our start to the season - we are not comfortable, we don't show the quality, we don't show the personality.
"I really trust this team and these players, they are good players, they are working well and I really trust that they have the quality.
"[But] at the moment we haven't showed anything - it can be my fault, or something like this, but anyway, independent of any shape we play, if you cannot do the simple things it's complicated."
Luton, meanwhile, were coming off the back of a 5-0 home drubbing by Birmingham last weekend and looked much more solid this time out, goalkeeper Simon Sluga having little to do with the Hatters also occasionally posing a threat in attack.
They have seven points from their first five games but it could have been more had Cornick's shot been inches lower afte team-mate Adebayo successfully closed down the dawdling Foderingham in the Blades goal.
Jokanovic made only one change from his side's Championship defeat by Huddersfield, Billy Sharp coming in for £23.5m striker Rhian Brewster, but he and strike partner Oli McBurnie were barely in the game as the visitors registered just one shot on target despite having 68% possession.
Luton manager Nathan Jones told BBC Three Counties Radio:
"I felt we were the better team - they had more possession than us but it was all in front of us - and then we had the better chances.
"They've got some wonderful players and have been either a top two Championship side or a Premier League side for the last three seasons, so it shows that we are competing.
"We're constantly punching above our weight and to respond in the manner we did after taking a few punches on the chin this week, I'm really proud of that group."
