Sheffield United goalkeeper George Long made a number of fine saves as his promotion-chasing side had to settle for a point against Leyton Orient.
Both teams had good chances in the first half, Neill Collins firing wide for the hosts and Shaun Batt having his shot saved by Long at the other end.
And the Blades keeper made an excellent double save from Romain Vincelot and sub Dave Mooney after the break.
Ryan Flynn has the Blades' best chance but his shot cannoned off the post.
Dominic Poleon also went close but slid his shot wide when clear of the Orient defence.
The Blades lose top spot in League One as they were overtaken by Doncaster, who scored an injury-time goal to win at Shrewsbury, while Orient climb a place to 12th.
United had the better of the opening exchanges, but the first half was short on quality chances.
The O's had a spell of pressure just before the break but, despite forcing a succession of corners, they were unable to really test Long.
It was a different story in the second period and Long needed to be in top form to deny Vincelot and Mooney in quick succession.
Mooney also had a late effort but was unable to find the target, while United had a chance to win it but Jamie Jones made a great save from Harry Maguire.
VIEW FROM THE DRESSING ROOM
Sheffield United manager Danny Wilson tells BBC Radio Sheffield:
"Frustrating. We always want to win at home but you got look back and its just not dropped tonight.
"Give them credit, they've come and flooded the midfield. They've flooded the back line and made it very difficult for us to get through them.
"We've just returned 13 points out of 15 which is a great return and if we do that in the next four or five games, we'll be more than happy.
"Yeah the fans want promotion as much as we do, we want promotion as well."