Ex-Liverpool managing director Christian Purslow believes Alexis Sanchez's move to Manchester United from Premier League rivals Arsenal was a "once in a generation" bargain.
Soon-to-be free agent Sanchez left Arsenal for United before the January transfer window closed, with out-of-favour playmaker Henrikh Mkhitaryan moving in the opposite direction to the Emirates Stadium as part of the swap deal.
Sanchez had appeared set to reunite with Pep Guardiola at runaway Premier League leaders Manchester City after a transfer broke down in August but Jose Mourinho and United hijacked the deal, luring the Chile international forward to Old Trafford.
"We will never quite know the sequence of events that led to that potential transaction winding away into a United purchase," Purslow told Sky Sports.
"It has the look from the outside, I don't know this to be true, that Arsenal out of nowhere had their dreams come true.
"Rather than being in a unilateral discussion with City taking their best player nearly on a free they had a little auction going when Mourinho and [Chelsea head coach] Antonio Conte both spoke up in early January that actually getting Sanchez was a once in a generation opportunity to buy a top player for not much money down."
Purslow added: "I think Arsenal suddenly had a little auction going. I suspect when Sanchez's agent said to Manchester City's executive team you might have to improve my deal up a bit because United are here - that [would have] felt like a breach in trust.
"They thought they had a handshake deal at best. I bet they were very angry about that and I suspect they thought actually let's walk away from this deal leaving Manchester United to sweep him up.
"Brilliant outcome for United, pretty good outcome for Arsenal on balance but I suspect not a very happy camp at City around the way that deal was conducted."
Sanchez made his Premier League debut as United crashed to a 2-0 loss at Tottenham Wednesday, allowing City to move 15 points clear atop the table.
