Match ends, Southampton 3, Norwich City 0.
Southampton recorded their first Premier League win of the season as they comfortably beat a Norwich side who played for an hour with 10 men.
Norwich had Steven Whittaker sent off just past the half-hour mark when he received two cautions in three minutes.
Under heavy pressure, their resistance broke just before half-time as Graziano Pelle converted Sadio Mane's pass.
Dusan Tadic rifled another Mane pass into the top corner after the break before then tapping home.
Southampton were already well on top before defender Whittaker was dismissed, cautioned first for a tussle with Matt Targett and then for pulling back Tadic, who angered the away fans by waving an imaginary card.
Norwich keeper John Ruddy denied James Ward-Prowse, Mane and Jay Rodriguez as Southampton dominated, while Cameron Jerome's mistimed header was the visitors' best chance.
Can Koeman replicate his debut season heroics?
Saints manager Ronald Koeman enjoyed an impressive first season in England, guiding the club to seventh in the Premier League and into European football.
Things haven't gone so well this campaign, having already been knocked out of the Europa League and without a league win in their first three matches.
However, there was no panic on Sunday as the Saints dominated possession, even before Whittaker's red card. With Mane and Tadic a constant threat and striker Jay Rodriguez returning to fitness, Koeman will believe he has the resources for another good season.
Will the Saints keep the vultures away?
Koeman worked heroics last season, taking over a club who sold five players for £92m and leading them to European qualification for the first time in 12 seasons.
They will hope they do not have to rebuild again with midfielder Victor Wanyama left out of the squad, due to being unsettled after transfer speculation, and having already rebuffed Manchester United's interest in Mane.
Kenya's Wanyama is a physical force for the Saints and, while they coped without him against 10-man Norwich, his departure would be a big blow to their season hopes - as would the loss of the speedy Mane.
Do Norwich need reinforcements?
The Canaries have made a decent start to the season but were completely outplayed at St Mary's, partly due to their numerical disadvantage.
Eight players in Norwich's starting line-up at Southampton featured for them when they went down in 2013-14 and, with just one shot on target, Neil will be keen to add more attacking quality.
Man of the match: Dusan Tadic
Southampton boss Ronald Koeman: "It was a very positive result. Last Thursday was a big disappointment and it's always hard to start well, but we played very well at the beginning.
"The goal before half time broke the game open, and I'm very happy about how we played in the second half - there was lots of pressing and we created some great chances.
Southampton forward Dusan Tadic: "The defeat in midweek against Midtjylland was maybe a good wake-up call for us and we showed a great reaction today."
Norwich City manager Alex Neil: "The manner in which we relinquished the away record was disappointing. That wasn't like us. We didn't start well, even 11 v 11 we were poor, our use of the ball was poor.
"I think Whittaker's first yellow was a bit soft, he was just trying to get back in position, but they were silly decisions and they cost us. We didn't deserve anything from the game and we need to be better for the next match."
The stats you need to know
- Twelve of Graziano Pelle's 14 Premier League goals for Southampton have come at St Mary's
- There were just three minutes and seven seconds between Steven Whittaker's two yellow cards
- Southampton's victory was Alex Neil's first away defeat as Norwich manager in 15 matches in all competitions
- It was only the eighth home win of the Premier League season so far
- This is the first time Mane has provided two assists in a single Premier League game
- The Saints have kept consecutive Premier League clean sheets for the first time since February
Former Leicester striker Steve Claridge on BBC Radio 5 live: "As soon as Norwich went down to 10 men it was game over. Ronald Koeman was nice and positive, he put two up front and went for the jugular. You just wonder if Norwich lack a little bit of Premier League quality."
After the international break, Southampton will hope to make it back-to-back Premier League wins when they travel to West Brom on 12 September. Norwich entertain fellow Premier League newcomers Bournemouth on the same day.
- 2Cédric SoaresSubstituted forMartinaat 72'minutes
- 6José Fonte
- 10ManéSubstituted forJuanmiat 81'minutes
- 8DavisSubstituted forRodriguezat 45'minutes
- 2WhittakerBooked at 31mins
- 18DorransSubstituted forJohnsonat 70'minutes
- 14HoolahanSubstituted forWisdomat 32'minutes
- 10JeromeSubstituted forHooperat 89'minutes
- 29van Wolfswinkel
- Jonathan Moss
- Shots on Target
Second Half ends, Southampton 3, Norwich City 0.
Attempt missed. Gary Hooper (Norwich City) right footed shot from the centre of the box misses to the left.
Attempt saved. Bradley Johnson (Norwich City) left footed shot from outside the box is saved in the bottom right corner. Assisted by Nathan Redmond.
Foul by Maya Yoshida (Southampton).
Gary Hooper (Norwich City) wins a free kick in the defensive half.
Substitution, Norwich City. Gary Hooper replaces Cameron Jerome.
Corner, Norwich City. Conceded by Maya Yoshida.
Corner, Southampton. Conceded by Jonny Howson.
Attempt missed. Alexander Tettey (Norwich City) right footed shot from outside the box is high and wide to the right. Assisted by Bradley Johnson.
Attempt missed. James Ward-Prowse (Southampton) right footed shot from outside the box is close, but misses to the left from a direct free kick.
Substitution, Southampton. Juanmi replaces Sadio Mané.
Sadio Mané (Southampton) wins a free kick in the attacking half.
Foul by Jonny Howson (Norwich City).
Maya Yoshida (Southampton) wins a free kick in the defensive half.
Foul by Bradley Johnson (Norwich City).
Attempt missed. Jay Rodriguez (Southampton) right footed shot from the left side of the box is high and wide to the right. Assisted by Dusan Tadic.
Substitution, Southampton. Cuco Martina replaces Cédric Soares.
Attempt missed. Jay Rodriguez (Southampton) right footed shot from the right side of the box is close, but misses to the right. Assisted by Cédric Soares.
Substitution, Norwich City. Bradley Johnson replaces Graham Dorrans.