Manchester United survived Casemiro's early red card and an impressive display by rock-bottom Southampton as a pulsating Old Trafford encounter ended goalless.
Erik ten Hag stressed the need for his side to be at their best as the Red Devils returned to Premier League duty for the first time since last weekend's historic 7-0 thrashing at rivals Liverpool.
United showed impressive character to bounce back and beat Real Betis on Thursday and again produced a display of strength to draw 0-0 with Southampton after Casemiro's second sending-off of the season.
The Brazil international looked devastated when referee Anthony Taylor brandished a straight red in the 34th minute after the VAR advised him to review the challenge on Carlos Alcaraz on the pitchside monitor.
United felt aggrieved by that decision, just as they did when penalty appeals were rejected before the break.
United goalkeeper David de Gea told Sky Sports: “It should be a game to win today but the game changed when we lost a man in the team.
“We tried our best to score but it was difficult. They had some chances but in the end we showed good team spirit. We have to take the point and keep going.”
Saints' performance belied their wretched season to date and Aaron Wan-Bissaka cleared off the line shortly after the break, with James Ward-Prowse seeing a free-kick graze the bar.
De Gea and Gavin Bazunu produced outstanding saves across this scoreless encounter, including the latter tipping a Bruno Fernandes shot on to the post before Kyle Walker-Peters hit the woodwork at the other end.
Man United 0-0 Southampton - in pictures
United's final Premier League match of the month ended in a hard-fought point, which represented a positive start to a key week as Ruben Selles' Saints battle for survival.
Elsewhere, Said Benrahma's penalty lifted West Ham back out of the relegation zone after a 1-1 draw with Aston Villa.
The Hammers fell behind to an Ollie Watkins header but Benrahma hit back from the spot after Lucas Paqueta was fouled.
West Ham started the day in the bottom three after Bournemouth's shock win over Liverpool.
They knew a victory would lift them 14th, but they were unable to find a winner with Danny Ings drawing a blank against his old club.
Nonetheless, a draw moved them up to 17th ahead of Bournemouth on goal difference and stretched West Ham's unbeaten streak against Villa to 10 matches, going back to 2015.
West Ham defender Kurt Zouma told Sky Sports: “I think it should have been three points. We played a good game and had many chances but just couldn't score. Obviously we need to get wins.
“That was their only chance and they scored. We kept the focus and the belief to come back. We should have won but we got a point and need to move on.”
