Former Manchester United defender Phil Neville believes his old side have been forced into a big-money move for Alexis Sanchez this month because of Liverpool.
Arsenal star Sanchez, 29, is on the verge of sealing a switch to Old Trafford.
Sanchez had been expected to join Manchester City this month, but the Premier League leaders pulled out of a deal, leaving United with a free run at the Chilean, reports the Liverpool Echo.
United have made their move for the former Barcelona star, and look set to complete a deal which will reportedly earn Sanchez around £500,000 a week.
But speaking on Radio 5 Live, former United defender Neville believes they have been forced to act after Liverpool's recent improvement.
The Reds are now 18 games unbeaten in all competitions, their most recent victory coming in Sunday's thrilling 4-3 win over Manchester City.
With Liverpool just three points behind second-placed United, Neville thinks his old club had to do something to repel them.
"I think it's a sensational deal for Manchester United," Neville said. "I would have thought maybe a month ago Alexis Sanchez wouldn't have come on the radar.
"All of a sudden, every now and again there comes a signing that you have to make, or if he's available you have to try and make.
"Sanchez, because of the form of Liverpool in particular... I think it's maybe hurried up the need for someone to come in and, not secure United's second place, but actually give them a massive, massive boost.
"I think United will finish in the top four and in second place but the form of Liverpool must be a worry because they're playing unbelievable at this moment in time.
"And the Sanchez deal, I think not only does it lift Manchester United, I think maybe taking him off City gives them a little bit of a boost as well."
Liverpool had wanted Sanchez in 2014, when he was still at Barcelona, but the South American opted to join Arsenal instead.