United took the lead after 17 minutes when Kieran Gallagher swung over a free kick and Lee Harvey headed in.
Robins levelled on 24 minutes through a long range free kick by Smith, Simon Brown was slow to react and the ball went in at the near post.
Two minutes later Phil Mason completed a flowing move to restore the lead with a thundering 18 yard shot.
Soon after, Harvey went close with a back header which went just wide.
On 53 minutes Corey Browne headed over Searle to make it 3-1 and United looked set to go eight points clear at the top.
But on 60 minutes a mistake by Ian King let in Smith to smash past Brown from close range, and on 70 minutes a cross from Haynes found the unmarked Newbery who volleyed home.
In the closing stages Searle preserved a surprise point with excellent saves from Gary Crawshaw and Ian Rutherford.