Louis van Gaal's need for defensive reinforcements was highlighted in Manchester United's loss to Paris Saint-Germain.
Manchester United's defenders were put to the sword as Paris Saint-Germain won the United States leg of the International Champions Cup via a 2-0 victory in Chicago on Wednesday.
Much of the build-up was centred on Angel di Maria's imminent switch from United to PSG, and manager Louis van Gaal's apparent unwillingness to invest in a new centre-back, following reports prime transfer target Sergio Ramos has agreed a new deal to remain at Real Madrid.
And the Dutchman was handed a timely wake-up call before the club's Premier League opener against Tottenham on August 8 as PSG's attack ripped United's defence to shreds in front of 61,351 fans at Soldier Field.
United's back four of Matteo Darmian, Phil Jones, Daley Blind and Luke Shaw were up against it from the outset as Blaise Matuidi and Zlatan Ibrahimovic put the French champions in control at half-time.
France international Matuidi outmuscled Jones and Shaw for the opening goal in the 25th minute, and the United duo were at fault again nine minutes later as Sweden captain Ibrahimovic doubled the lead with ease.
PSG's third win in four matches ensured they topped the ICC standings ahead of New York Red Bulls on goal difference, and a point clear of defending champions United.
Bastian Schweinsteiger started his first match for United as Van Gaal named close to a full-strength XI, with Wayne Rooney, David de Gea, Memphis Depay, Juan Mata, Darmian, Shaw and Michael Carrick all included.
PSG fielded an equally as strong line-up - Ibrahimovic, Thiago Silva, Lucas Moura, Marco Verratti, Maxwell and Matuidi were selected.
De Gea - starting in goal for the second consecutive match amid interest from Real Madrid - almost gifted PSG a second-minute opener after kicking the ball straight to Ibrahimovic but the striker skied his shot over the crossbar.
United's attack appeared disjointed, though Rooney linked up with Memphis in the 16th minute, cutting the ball back to the latter, who struck his effort wide of the post.
PSG - playing on the counter attack - opened up United's defence nine minutes later as Matuidi broke the deadlock moments after Mata had a goal ruled out for offside.
Shaw and Jones were unable to deal with Matuidi, who showed tremendous strength before poking the ball past De Gea with relative ease.
United were carved up again nine minutes later, this time Ibrahimovic the beneficiary. Maxwell picked out an unmarked Ibrahimovic between Jones and Shaw on the edge of the six-yard box and the striker made no mistake from close range.
Depay came close to reducing the deficit three minutes later, after Kevin Trapp parried the Dutchman's free-kick into danger, though PSG somehow managed to clear their lines.
As expected, both teams made substitutions at the break, with David Luiz, Edinson Cavani, Marquinhos, Morgan Schneiderlin and Andreas Pereira introduced, while De Gea was withdrawn.
The half-time changes stemmed the flow for United, but they still struggled to create anything dangerous, as their attack remained disorganized with Rooney isolated up front.
And while opportunities were at a premium in the second half, substitute Youssouf Sabaly came close to extending PSG's advantage with a powerful strike that flashed just wide of the post with 13 minutes remaining.