Grant won the Battle of Port Gibson. Advancing toward Port Gibson, Grant's army ran into Confederate outposts after midnight. Union forces advanced on the Rodney Road and a plantation road at dawn, and were met by Confederates. Grant forced the Confederates to fall back to new defensive positions several times during the day; they could not stop the Union onslaught and left the field in the early evening. This defeat demonstrated that the Confederates were unable to defend the Mississippi River line; the Federals secured their needed beachhead.