However, when Norwich went in at half time with a 2-0 lead thanks to goals from Mark Fotheringham and Wes Hoolahan, it looked as if Bryan Gunn's rejuvenated Canaries were on course for another three points under his guidance.
Kayne McLaggon's deflected shot pulled a goal back and the point was secured for the Saints when Marek Saganowski slipped his marker Jonathan Grounds to score the equaliser with a header.
The Saints kicked off attacking the River End goal and frustrated the Canaries by getting players behind the ball in numbers.
In the 28th minute, Davis was called into action to turn Hoolahan's shot for a corner.
A minute later, Lee Holmes limped off to be replaced by McLaggon.
Davis then saved from Jamie Cureton who then set up Fotheringham for the opening goal.
Cureton's pass from the left of the penalty area looked to be heading for Lee Croft until Fotheringham raced in and his right-foot shot from 12 yards beat Davis low to his left.
Within two minutes, Norwich had netted again when Fotheringham played a free-kick to Hoolahan on the City left and his left-foot shot from some 28 yards curled beyond Davis's left hand on its way into the top corner.
Twelve minutes into the second half, Southampton pulled a goal back when Fotheringham cleared Simon Gillett's left-wing corner to McLaggon on the edge of the penalty area and his right-foot shot took a wicked deflection that beat David Marshall to his left.
This lifted the visitors for a few minutes, but the home side went in search of a third goal.
Instead of which a moment of indecision in the Norwich defence allowed Saganowski to score with a downward header from Lloyd James' right-wing cross.
The Saints then had to withstand intense pressure from the Canaries in order to gain a hard-earned point.