Rain prevented Hampshire from completing a clean sweep of their Friends Life t20 south group fixtures after their clash with bottom-placed Middlesex was washed out.
Having won all of their previous seven matches, the Royals expected to conclude their home campaign with a win over Middlesex but never got the chance to complete the task.
Hampshire captain Dominic Cork chose to bat first in gloomy conditions and his team had reached 116 for two from 13 overs before rain brought a premature end to proceedings.
The match had already been reduced to 18 overs per side when umpires Nick Cook and Peter Hartley decided there was no further chance of any action.
In the 13 overs available to Hampshire, they lost opener Jimmy Adams when on 38 and big-hitting James Vince at 77.
Adams was the first to go when he lofted Steven Crook to Scott Newman after making 16 from the first five overs.
Vince (26) was in fine form until he drove Neil Dexter to Tim Murtagh in the 10th over.
Neil McKenzie and Sean Ervine were in full flow in an unbroken stand of 49 for the third wicket when the rain intruded.
Ervine had smashed his way to 34 not out from only 14 balls in an innings which included five fours and a six.
McKenzie was no less aggressive, striking four fours in his 38 not out but Hampshire were denied the opportunity to build a testing total.
Hampshire finished their 16 zonal fixtures top of the table with 23 points, thereby guaranteeing a home match in the quarter-finals.