SOUTHAMPTON 1 SUNDERLAND 1
20. Keiren Westwood
12. Ondrej Celustka
16. John O'Shea
21. Modibo Diakite
14. Jack Colback 54'
11. Adam Johnson
8. Craig Gardner
7. Sebastian Larsson
23. Emanuele Giaccherini 82'
28. Stephane Sessegnon 46'
17. Jozy Altidore
Subs
6. Cabral
10. Connor Wickham 82'
15. David Vaughan 54'
19. David Moberg Karlsson
25. Vito Mannone
27. Dong-Won Ji 46'
29. Valentin Roberge
It had looked like an early goal from the diminutive Emanuele Giaccherini would see Paolo Di Canio's men take three points back to the north east.
Standing at just 5ft 5in, the smallest player of the pitch headed home a Sebastian Larsson corner unmarked in just the third minute.
Poor finishing, fine goalkeeping from Kieren Westwood and plain old bad luck looked set to deny Saints, only for centre-back Fonte to head home two minutes from time.
It was just reward for Mauricio Pochettino's side, who came into the clash buoyed by a fine opening-day win at West Brom and another big-money acquisition.
Following moves for Dejan Lovren and Victor Wanyama, Dani Osvaldo arrived this week from Roma for a fee that could reach £14.5million.
The forward was named amongst the substitutes at St Mary's, where another Italy international struck the first blow.
Larsson sent across a corner from the left found Giaccherini unmarked and he nodded home to the delight of the hardy 1,867 travelling fans.
It was hardly the start Southampton wanted but one they responded well to.
Rickie Lambert slipped through a fine ball to Jay Rodriguez, who slotted past Westwood and wheeled away in celebration - only for the linesman to rule the sixth-minute leveller out for offside.
Saints again came close 10 minutes later, with Westwood this time the man in the way.
James Ward-Prowse, one of three 18-year-old academy graduates in the starting line-up, sent over a looped cross to Lambert, with only an exquisite Westwood save down to his right preventing the England international heading home.
Neither side was managing to dominate play but Sunderland were looking the more confident, epitomised by a cheeky in-swinging Larsson corner that almost caught Artur Boruc off guard.
A Rodriguez snap shot deflected wide off Craig Gardner when play returned to the other end, with Jozy Altidore proving a handful for Southampton's defence.
Lambert powered a header over at the back post, while Altidore, Fonte and Adam Lallana all had penalty appeals waved away before half-time.
Nathaniel Clyne and record-signing Osvaldo were introduced for the second period, with the latter close to having an immediate impact.
The Italian's deft pass saw Lallana with a clear shot on goal, only for Modibo Diakite to swoop in with a fantastic, late tackle.
The Saints captain saw a right-footed half volley curl just wide shortly afterwards, before an Osvaldo cross found Rodriguez, only for the Saints attacker to head straight at Westwood from close range.
Westwood did well to tip a long-range Lambert strike around the post but Saints were still struggling at the back, with only the onrushing Boruc preventing Altidore doubling the Black Cats' advantage.
It was Southampton in the ascendancy, though, and they kept knocking on the visitors' door.
Lambert and Rodriguez were the next to threaten, although the intensity began to peter out with 15 minutes remaining.
Osvaldo headed into the ground under pressure from John O'Shea as the match entered the closing stages as tempers began to fray.
Ironic cheers met referee Lee Mason's award for a foul on the new boy late on - a decision that led to Saints equalising at the death.
Ward-Prowse floated in the free-kick and centre-back Fonte met the ball with a powerful header that at last beat Westwood.
Rodriguez saw a shot deflect wide as Saints pushed for another in stoppage time, but there was to be no further goals.
SUNDERLAND v SOUTHAMPTON
2013/2014 Sat 24 Aug Southampton 1 - 1 Sunderland Premier League
2012/2013 Sun 12 May Sunderland 1 - 1 Southampton Premier League
Sat 22 Dec Southampton 0 - 1 Sunderland Premier League
2006/2007 Mon 09 Apr Southampton 1 - 2 Sunderland Championship
Sat 11 Nov Sunderland 1 - 1 Southampton Championship
2002/2003 Tue 28 Jan Sunderland 0 - 1 Southampton Premiership
Sat 28 Dec Southampton 2 - 1 Sunderland Premiership
2001/2002 Sat 23 Mar Sunderland 1 - 1 Southampton Premiership
Sat 15 Dec Southampton 2 - 0 Sunderland Premiership
2000/2001 Sat 28 Apr Southampton 0 - 1 Sunderland Premiership
Sat 11 Nov Sunderland 2 - 2 Southampton Premiership
1999/2000 Sat 01 Apr Southampton 1 - 2 Sunderland Premiership
Sat 18 Dec Sunderland 2 - 0 Southampton Premiership
1996/1997 Tue 22 Apr Sunderland 0 - 1 Southampton Premiership
Sat 19 Oct Southampton 3 - 0 Sunderland Premiership
1990/1991 Sat 13 Apr Southampton 3 - 1 Sunderland First Division
Tue 01 Jan Sunderland 1 - 0 Southampton First Division
1984/1985 Tue 29 Jan Southampton 1 - 0 Sunderland First Division
Sat 25 Aug Sunderland 3 - 1 Southampton First Division
1983/1984 Sat 11 Feb Southampton 1 - 1 Sunderland First Division
Sat 10 Sep Sunderland 0 - 2 Southampton First Division
1982/1983 Sat 19 Feb Southampton 2 - 0 Sunderland First Division
Sat 09 Oct Sunderland 1 - 1 Southampton First Division
1981/1982 Sat 08 May Southampton 1 - 0 Sunderland First Division
Wed 10 Mar Sunderland 2 - 0 Southampton First Division
1980/1981 Sat 31 Jan Southampton 2 - 1 Sunderland First Division
Sat 23 Aug Sunderland 1 - 2 Southampton First Division
1977/1978 Sat 04 Mar Sunderland 0 - 0 Southampton Second Division
Sat 08 Oct Southampton 4 - 2 Sunderland Second Division
1975/1976 Sat 27 Mar Sunderland 3 - 0 Southampton Second Division
Sat 06 Dec Southampton 4 - 0 Sunderland Second Division
1974/1975 Tue 14 Jan Southampton 1 - 1 Sunderland Second Division
Sat 24 Aug Sunderland 3 - 1 Southampton Second Division
1969/1970 Sat 07 Mar Southampton 1 - 1 Sunderland First Division
Sat 22 Nov Sunderland 2 - 2 Southampton First Division
1968/1969 Sat 08 Mar Southampton 1 - 0 Sunderland First Division
Sat 17 Aug Sunderland 1 - 0 Southampton First Division
1967/1968 Sat 02 Mar Sunderland 0 - 3 Southampton First Division
Sat 25 Nov Southampton 3 - 2 Sunderland First Division
1966/1967 Wed 31 Aug Southampton 3 - 1 Sunderland First Division
Wed 24 Aug Sunderland 2 - 0 Southampton First Division
1963/1964 Sat 11 Apr Southampton 0 - 0 Sunderland Second Division
Sat 30 Nov Sunderland 1 - 2 Southampton Second Division
1962/1963 Sat 04 May Sunderland 4 - 0 Southampton Second Division
Sat 22 Sep Southampton 2 - 4 Sunderland Second Division
1961/1962 Sat 07 Apr Sunderland 3 - 0 Southampton Second Division
Sat 18 Nov Southampton 2 - 0 Sunderland Second Division
1960/1961 Mon 17 Apr Sunderland 3 - 1 Southampton Second Division
Sat 15 Oct Southampton 3 - 2 Sunderland Second Division