Manager Ole Gunnar Solskjaer was understandably frustrated after Chris Wilder led rock-bottom Sheffield United to a stunning Premier League win at Old Trafford. The title-chasing Red Devils were handed one of the biggest shocks in a surprise-packed campaign as the Blades inflicted the hosts' first top-flight defeat since November 1. Former Manchester City youth prospect Kean Bryan opened the scoring in a first half in which Anthony Martial saw an equaliser ruled out for an apparent foul by Harry Maguire on Sheffield United goalkeeper Aaron Ramsdale. Skipper Maguire did eventually find a leveller in the second half but Solskjaer's comeback kings floundered rather than rallied. The Blades capitalised on some atrocious defending as substitute Oliver Burke struck home off of Axel Tuanzebe to seal a 2-1 win – only their second Premier League triumph of a poor season. "Well, of course we're disappointed," Red Devils boss Solskjaer said. "Any result in the Premier League this season shouldn't surprise anyone. But then again, very disappointed we couldn't put a better performance on. "It was down to us to put a performance up and we just couldn't find an opening behind or round or between a very compact and good Sheffield United defence. "The big moments went against us. If you look at it, Billy Sharp's been around the place and he knows how to put a goalkeeper off and that's a definite foul on him [before Bryan's opener], so David [De Gea] can't get up. "For me, the referee makes a mistake by blowing the whistle [for a foul by Maguire] on our goal [from Anthony Martial in the first half] but that happens." Solskjaer was annoyed by the poor defending in the build-up to Burke's heavily-deflected winner and knows his side need to get their spark back quickly. "That little spark, that edge, we didn't have that extra creativity, imagination, the X factor we've had," the Norwegian said. "It's happened, we look at it, agree it is not good enough and go again." This was the Blades' first win against Manchester United since 1993