The struggling Manchester United invested big bucks to take Colombian Radamel Falcao on the last day of the summer transfer period, according to reports. 

The English club got the Monaco striker on loan for $9 million (or  £20 million), with an option to buy, an Associated Press report revealed, as posted on ABC News. The midnight deal was inked after the team sought an extension to the 11 p.m. transfer deadline, The Telegraph said.

United was granted the midnight extension after grabbing the one-year-loan opportunity and requesting extra time to process paperwork required by the Fifa Transfer Matching System, The Telegraph reported. The team waited until the early hours of Tuesday—1:30 a.m.—to announce the deal.

The Falcao move was a response to the pressure the record 20-time English champion has been under following the end of Alex Ferguson's 26-year term as manager in May last year, AP reported. United failed to win any of its opening four matches under manager Louis van Gaal, who was hired after a performance slump under David Moyes last season.

"I am looking forward to working with Louis van Gaal and contributing to the team's success at this very exciting period in the club's history," Falcao said, as quoted by AP. Meanwhile, Van Gaal said Falcao "is one of the most prolific goalscorers in the game," citing the forward's stellar appearance-to-goal ratio.

Monaco took him from Atletico Madrid, where he had 70 goals in 91 appearances, AP reported. Before that, he netted 72 goals in 87 games for Porto, based in Portugal.

Falcao joined Monaco last year for 60 million euros (then $78 million), but was unable to play in the last half of the previous season and at the World Cup because of injury. He leaves a Champions League qualifier for one that is not participating in any European competition this season, AP noted.

In Van Gaal's system, Falcao could be coupled with Robin van Persie up front, while team captain Wayne Rooney could be at midfield, AP said.

Spanish football expert, Guillem Balague, reportedly said Falcao tried to pull off a Real Madrid transfer, before settling for United, Sky Sports said.

He told Sky Sports that Jorge Mendes, who represents Falcao, "tried all year" to see his player sign with Real Madrid, although the European champion saw Javier "Chircharito" Hernandez as the player that better complements Karim Benzema.

Arsenal was not considering Falcao despite the gap left by injured striker Olivier Giroud, Sky Sports added.

According to The Telegraph, after Monaco and Falcao's representatives told City and Arsenal about the £10-million loan fee on top of the player's £18-million annual salary, negotiations with the Emirates or Etihad failed.

"And with Real Madrid also pulling out of the race to sign Falcao, United accelerated their interest in the striker on Saturday evening after agreeing to pay a reduced £6 million loan fee and the player's wages, with sizeable a reduction on the tax-free salary paid by Monaco," The Telegraph noted.

United has spent around $250 million on players after a seventh-place finish last season, AP said.