The decisive strike came in the sixth minute when Sutton controlled a long ball from Jeff Kenna, rounded Chris Perry and rolled his shot past the Wimbledon goalkeeper, Neil Sullivan, for his 10th goal of the campaign.
"He's certainly had a marvellous start to the season and if he continues to play as well as he has been doing and keeps scoring it will be harder and harder for people selecting the team to leave him out," the Rovers manager, Roy Hodgson, said.
Stan Collymore, the Aston Villa striker who is one of the players keeping Sutton out of the England squad, had a less satisfying day, although the Midlanders also won 1-0 away, at Bolton. He was sent off for violent conduct in the 90th minute. By then, Savo Milosevic, scorer of the only goal of the tie in Villa's narrow Uefa Cup win over Bordeaux, was their hero again when he gave them a 12th-minute lead, heading in Fernando Nelson's right wing cross from six yards out.
Wanderers, with Nathan Blake starting a three-match suspension, gave an immediate debut to the former Wimbledon striker, Dean Holdsworth, signed for pounds 3.5m last week, but he made little impression as Bolton pressed fruitlessly for a point.
Before yesterday's match against West Ham, Southampton fans waved yellow cards in protest at the club's transfer dealings and poor start (four points from the first nine games) and then repaid their former Israeli international midfielder, Eyal Berkovitch, who was instrumental in keeping them in the Premiership last season, with taunts of "Judas".
Once the game started, the Saints, able to field a full-strength side and with Matthew Le Tissier orchestrating matters, should have gone ahead when the Channel Islander's pass set up Ken Monkou, but the central defender missed from six yards. The game turned when Egil Ostenstad came on after 52 minutes. Two minutes later he gave Southampton the lead by bundling the ball out of Ludek Miklosko's grasp and forcing it over the line.
The Hammers had not won at the Dell in the nine previous visits and duly fell apart after that controversial opening goal, Kevin Davies and Jason Dodd scoring within four minutes of each other.
In Scotland, Rangers, who were knocked out of their second European cup competition of the young season by Strasbourg on Tuesday, fought back from 3-1 down against Hibernian at Easter Road to win 4-3, Marco Negri scoring the first and last to take his season's total to 18.Reuse content