Lovren seemed to connect with the ball first in the death throes of frantic contest just ahead of Phil Jones and Adam Lallana from substitute James Ward-Prowse's corner to give the visiting side a point they were worth after a stout performance.
Manchester United seemed set to collect their second straight league win, and ease the pressure on new manager David Moyes, courtesy of Robin van Persie's expert finish on 26 minutes.
There was a slight hint of offside when Wayne Rooney bounded onto the impressive Adnan Januzaj's pass.
Visiting goalkeeper Artuc Boruc raced from his line to make a fine stop, but the ball broke kindly for Van Persie to round the stranded Boruc before sliding a finish into the gaping net.
Southampton were the brighter side in the second half, and earned their reward in the death throes of a frantic afternoon. The point keeps Mauricio Pochettino's side in the top four with United in eighth spot, eight points behind leaders Arsenal.
25' - OSVALDO CHANCE: Golden chance for Osvaldo! Rooney loses the ball under pressure from Wanyama. Lallana on the attack, but his team-mate can't get any power on the finish from the pass. Easy take for De Gea.
26' - VAN PERSIE POUNCES: Van Persie scores on the rebound after Boruc had saved from Rooney. Fine finish with Boruc out of his goal and United have the lead. Lovely pass from Januzaj to pick out Rooney.
28' - ROONEY UNFORTUNATE: Fine turn and shot by Rooney from Nani's pass, but the shot comes back off the bar from 18 yards.
66' - VAN PERSIE HITS BAR: Lovely header from Van Persie to glance the ball at goal from Rooney's delivery. Boruc wouldn't have got there.
68' - BORUC BRILLIANCE: The Polish goalkeeper shows his class to make two outstanding saves to keep out Nani then plunge to his right to repel a raking Januzaj effort from distance.
87' - DE GEA DEFIANCE: Saints pushing for this equaliser. This time the home goalkeeper stands tall to keep out a thumping Clyne hit at his near post.
89' - LOVREN LEADS CELEBRATIONS: The big Saints defender races to the visiting fans after bundling the ball into the net from close range. Lallana claims last touch, but Lovren is taking the credit.
Robin van Persie scored his 126th Premier League goal, just one goal short of Jimmy Floyd Hasselbaink as the leading Dutch Premier Leaguie scorer. Van Persie’s 126 goals have moved him level with Robbie Keane in joint-11th place in the Premier League’s all-time goalscorers.
Man Utd are unbeaten in their last 51 Premier League matches when leading at half-time – (48 wins, three draws) – since the 2-1 defeat at Chelsea, March 1st 2011.
Manchester Utd fail to win successive Premier League home matches for the first time since 2007 – when they failed to win in three in a row, April-Aug 2007.
Dejan Lovren has been credited with Southampton’s goal – his previous Saints goal came in the 1-0 win at Anfield, September 21st. He has not scored more than once in a League season previously in his career.
Robin van Persie scored his first Premier League goal since September 14th and his first from open play since scoring twice on the opening day.
TALKING POINT: Where do United go from here? Into the Champions League and a match with Real Sociedad. Not very convincing form in the Premier League. Could have few complaints about this result. Certainly need to find some form soon with leader Arsenal suddenly eight points clear of them.
MAN OF THE MATCH
Artur Boruc (Southampton): So many impressive players in the visiting side, but the Poland goalkeeper - controversially dropped from his country's 2-0 defeat to England in midweek - gets the nod for two brilliant stops when United looked set to add a second goal midway through the second period.
Manchester United: De Gea 7, Rafael 6, Jones 6, Evans 6, Evra 6, Nani 6, Carrick 6, Fellaini 4, Januzaj 7, Rooney 7, Van Persie 6. Subs: Giggs 6, Smalling 5, Welbeck 6
Southampton: Boruc 8, Clyne 8, Fonte 7, Lovren 8, Shaw 7, Wanyama 8, Schneiderlin 7, S. Davis 6, Lallana 8, Rodriguez 7, Osvaldo 5. Subs: Lambert 6, Ward-Prowse 6, Guly 6
THE MATCH IN A TWEET