Friday night's FA Cup elimination against Middlesbrough was the latest in a series of blows Manchester United have endured in recent weeks. Their defeat on penalties came after an underwhelming transfer window that saw multiple departures and no new arrivals.Manchester United@ManUtdUnited exit the #FACup after defeat in the shootout.#MUFC4:27 AM · Feb 5, 2022108551802United exit the #FACup after defeat in the shootout.#MUFCManchester United had a disappointing 2022 January transfer windowDespite being linked with a host of midfielders, the Red Devils could not add reinforcements in the winter window.They also unexpectedly lost Mason Greenwood, who has been indefinitely suspended. Meanwhile, the club blocked Jesse Lingard's push for a move away, and are now set to lose him for free at the end of the campaign.Their FA Cup elimination means United have been knocked out of both domestic cups. The Champions League remains their only real shot at a trophy this season, with the Premier League being all but out of reach. Recent results suggest that the Red Devils' failure in the winter window could come back to haunt them.On that note, here's a look at five players whom Ralf Rangnick and co. should have tried to sign last month:#5 Denis ZakariaDenis Zakaria drives forward with the ball for Borussia Monchengladbach.The Red Devils were reportedly tracking Borussia Monchengladbach's 25-year-old Swiss midfielder Denis Zakaria in the first half of the 2021-22 season. His contract was set to run out at the end of the campaign, meaning the Bundesliga side were willing to sell him in a cut-price deal rather than risk losing him for free later.Although Zakaria has been plagued by injuries in recent seasons, his powerful frame, ability to drive forward with the ball and break up play made him the perfect target for Manchester United. The Red Devils' lack of a world-class defensive midfielder is currently their most glaring weakness.Fabrizio Romano@FabrizioRomanoDenis Zakaria to Juventus, done deal and here we go! Agreement reached for €5m fee plus add ons to Borussia Moenchengladbach. #JuventusContract agreed until June 2026. He’s prepared to fly to Turin in the next hours with his agents - he replaces Bentancur who joins Spurs.9:41 AM · Jan 30, 2022429033745Denis Zakaria to Juventus, done deal and here we go! Agreement reached for €5m fee plus add ons to Borussia Moenchengladbach. ⚪️⚫️ #JuventusContract agreed until June 2026. He’s prepared to fly to Turin in the next hours with his agents - he replaces Bentancur who joins Spurs. https://t.co/HYHsdjDBLeHowever, the club chose not to pursue Zakaria, which gave Juventus the chance to swoop in and sign the Swiss international for just over £7 million. On paper, it looks like a terrific bargain.#4 Amadou HaidaraAmadou Haidara in action for RB LeipzigRB Leipzig's 24-year-old midfielder Amadou Haidara was the first player Manchester United were linked with under Ralf Rangnick. The German tactician enjoyed successful spells as sporting director and manager of the Red Bull Sports Group.Rangnick's links with Leipzig meant fans were optimistic a deal might prove to be relatively straightforward. However, Haidara departed to play in the Africa Cup of Nations with Mali last month, which complicated any potential transfer.His passing between the lines and marauding runs from midfield could have helped United progress up the pitch quicker, and move the ball around better.Man United News@ManUtdMENAmadou Haidara 'didn't want' move away from RB Leipzig in January amid Manchester United links #MUFC manchestereveningnews.co.uk/sport/football…2:19 AM · Feb 3, 20221119Amadou Haidara 'didn't want' move away from RB Leipzig in January amid Manchester United links #MUFC manchestereveningnews.co.uk/sport/football…It now appears that any move will have to wait till the end of the ongoingseason.