Go Cory!!!
The important number here is not Gardner’s, but Udall’s. For an incumbent to only poll 42% is never a good sign, especially early in a campaign. The incumbent invariably has the advantage of name recognition, familiarity with record and positions on policy, etc. The challenger always is swimming uphill against these advantages.
For an incumbent to poll at 42%, the question has to be whether or not he can get to 51%. Usually a negative campaign is the only way. Of course, if Gardner makes a big gaff, it could turn around quickly as happened in the Claire McCaskill race.