Rotherham at least made the perfect starter, when youngster Jamie Green claimed his first goal for the club.
As Barnet failed to clear from the area Ryan Taylor reacted quickly to head down for Green who was in space and rifled a splendid low shot across the keeper from 15 yards.
Taylor found space and galloped forward as Barnet backed off and lashed a long range effort over the top before Mark Hudson went close after Green did well again.
Barnet's 20-year-old starlet Albert Adomah showed promise and his burst of pace saw him beat Green but his dangerous cross was well cleared.
And when Josh Wright shot from 20 yards, Cliff Akurang stretched to connect with a flick that ran kindly for Andy Warrington.
Hudson latched onto a ball headed down by Taylor but volleyed over from just outside the area. Then when Taylor cut inside from the left his low shot was just wide.
A double save from Warrington preserved Rotherham's lead just as Barnet threatened to draw level. Jason Puncheon sprinted down the left and smashed a 30-yarder that the Millers' number one parried and when Adomah drilled in the angled follow up Warrington did well again.
12 minutes into the second half Marc Joseph made a goal-line clearance, forcing the ball over the bar as Adomah looked certain to score by slipping his shot past Warrington.
Sub Jamie Yates then almost scored with his first touch for Rotherham but his shot on the turn hit the post.