Striker Fabio Borini suffered a shoulder injury as Liverpool lost to Roma in a pre-season friendly.
Borini, who spent last season on loan at Sunderland, went off in the first half. A fee of £14m had been agreed for his permanent return to Wearside, but that move could now be in doubt.
Former England international Ashley Cole made his debut for the Italian club at Fenway Park stadium in Boston.
A late own goal from Daniel Agger clinched a 1-0 victory for Roma.
Youngster Jordan Ibe was handed a start for the Reds, along with right-back Martin Kelly, who was included in England's Euro 2012 squad but whose career has since stalled due to injury problems.
Rickie Lambert went closest for Liverpool, drawing a fine save from Lukasz Skorupski on the hour.
Liverpool manager Brendan Rodgers said he did not know whether Borini would remain with Liverpool for the upcoming season.
"With regards his future we will wait and see," said Rodgers.
"We've had a substantial bid and it is something he is thinking about with his representatives but at the moment he is training and working with Liverpool."
Line-up (4-5-1): Jones; Kelly (Coady 68), Skrtel, Coates (Agger 60), Enrique (Robinson 46); Lucas, Allen (Henderson 77), Coutinho (Phillips 84), Borini (Can 12), Ibe (Suso 77); Lambert (Peterson 60).
Sporting Kansas City 1-4 Manchester City
Manchester City were convincing victors as they brushed aside MLS champions Sporting Kansas City 4-1.
21-year-old Argentine Bruno Zuculini, who is poised to complete his transfer to the club, and young Nigerian trialist Kelechi Iheanacho scored either side of goals from Dedryck Boyata and Aleksandar Kolarov.
Scott Sinclair and Stevan Jovetic, who both struggled for game time last season, were both handed starts but neither could get on the scoresheet.
Line-up (4-4-2): Caballero; Richards (Clichy 46), Boyata, Rekik (Nastasic 75), Kolarov; Navas, Fernando (Garcia 65), Zuculini (Huws 75), Sinclair (Leigh 89); Iheanacho (Denayer 92), Jovetic (Guidetti 65)
LA Galaxy 0-7 Manchester United
Manchester United also got off to an excellent start under new manager Louis van Gaal, as they cruised to a 7-0 win over LA Galaxy.
Wayne Rooney, Ashley Young and debutant Reece James each scored two apiece after Danny Welbeck opened the scoring.
Midfielder Ander Herrera made his debut for the club after signing from Athletic Bilbao.
Line-up: First half (3-4-1-2): De Gea; Smalling, Jones, Evans; Valencia, Fletcher, Herrera, Shaw; Mata; Rooney, Welbeck.
Second half (5-3-2): Lindegaard; Rafael, M Keane, Fletcher, Blackett, James; Herrera, Cleverley, Kagawa; Young, Nani.
Toronto FC 2-3 Tottenham
Tottenham secured a narrow 3-2 victory over Toronto FC as record signing Erik Lamela served notice of his quality.
The 22-year-old, a peripheral figure under Tim Sherwood last season, scored two first-half goals as new boss Mauricio Pochettino recorded his first win.
Andros Townsend, who missed the end of last season through injury, scored a late curling winner.
Left-back Ben Davies, newly signed from Swansea, made his debut for Spurs against Toronto, who were captained by former England player Jermain Defoe.
Line-up: First half (4-2-3-1): Friedel; Naughton, Kaboul, Veljkovic, Davies; Capoue, Mason; Eriksen, Lamela, Lennon; Soldado.
Second-half (4-2-3-1): Friedel; Walker, Dawson, Fryers, Rose; Carroll, Holtby; Townsend, Ceballos, Falque; Kane.
FC Dallas 0-2 Aston Villa
Aston Villa also enjoyed an encouraging win, overcoming FC Dallas 2-0.
Andreas Weimann and Charles N'Zogbia scored for Paul Lambert's side, while new signing Philippe Senderos made his debut.
Jores Okore, who suffered a frustrating debut season blighted by injury, started the match.
Line-up: First half (4-5-1): Given; Hutton, Okore, Baker, Stevens; Weimann, Bacuna, Herd, Gardner, Grealish; Bent.
Second half (4-3-3): Given; Lowton, Senderos, Clark, Bennett; Westwood, El Ahmadi, Delph; N'Zogbia, Agbonlahor, Richardson.
RZ Pellets Wolfsberger AC 1-1 Chelsea
Chelsea were held to a 1-1 draw in Austria by RZ Pellets WAC.
Petr Cech was handed a start in goal ahead of Thibaut Courtois but could not prevent the home side taking a shock lead.
Left-back Filipe Luis made his debut as teenage striker Jeremie Boga rescued the Blues with a late equaliser.
Line-up (4-2-3-1): Cech; Ivanovic, Zouma, Terry (c), Luis (Ake 60); Van Ginkel (Romeu 60), Matic (Chalobah 81); Salah (Swift 85), Baker (Boga h/t), Brown (Christensen 77); Bamford (Solanke 60).