Manchester United star Zlatan Ibrahimovic revealed his knee injury was worse than previously known, saying people would be shocked he returned.
The Swedish striker made his first appearance since April after coming off the bench in his side's 4-1 Premier League thrashing of Newcastle United on Saturday.
Ibrahimovic, 36, said his injury was far worse than previously known, although he preferred to keep the severity a secret.
"If people knew the real injury, they would be in shock that I was even playing. It was more than the knee but I will keep it personal – that's why I choose not to talk of it," he told UK newspapers.
"In my recovery I have not rushed anything. I have been out for six and half months. I have been following protocol and my schedule day by day.
"The only secret has been working hard. Those close to me know what I have been doing. I was working five, six hours a day."
Ibrahimovic scored 28 goals in all competitions for United last season before being released, only to sign a new one-year deal.
The veteran may be coming out of contract again, but he is unconcerned about his future.
"At the moment I am just thankful I can run and push it and play football again," Ibrahimovic said.
"I don't know what the future brings but what happens, happens. I am at the age where I can choose what I want to do.
"I don't sign five- or 10-year deals, I am just happy to be back playing and doing what I am good at.
"It's fantastic to be playing. Jose [Mourinho, United manager] said, 'Do whatever you want, I trust in you and you know what you have to do' so I was not worried.
"The contract is all paperwork and I do the physical work."
|Roberts injured in Broncos win against Eels|
|Atletico complete move for Villarreal star Rodri|
|Ozil, Gundogan not playing politics, says Low|
|Valencia complete permanent Kondogbia signing|
|Fairytale ending could be in the script, says World Cup-bound Vardy|
|Milwaukee police apologise to Bucks´ Brown over tasering|
|Television, crosswords and Nintendo - Koscielny´s remedy to World Cup heartache|
|World Cup not an audition for Barca or Madrid, says Germany star Werner|
|Neck injury rules Kohli out of Surrey stint|
|Nine LaLiga titles and 674 club games under nine managers - Iniesta in Opta numbers|
|49ers Enterprises takes stake in Leeds United|
|Manchester United should sell Pogba if he´s unhappy - Scholes|
|Andres Iniesta´s nine LaLiga triumphs with Barcelona|
|Andres Iniesta: The footballers´ footballer|
|Real Madrid v Liverpool: Salah has foundations in place for Ballon d´Or challenge|
|Iniesta´s Vissel Kobe move confirmed|
|Low upbeat over Neuer´s World Cup hopes|
|´No secrets´ in playoffs, says Celtics rookie Tatum|
|Real Madrid v Liverpool: Salah takes his chances better than Ronaldo - Opta|
|Cubs, Yankees find very different ways to lose|
|Cole hoping to see Rooney in MLS amid DC United links|
|LeBron feeling worn down following Cavs loss|
|Rahm enjoys ´traditional golf courses´|
|Upbeat Spieth eyeing first win of 2018|
|Ovechkin leads Capitals into Stanley Cup Finals|
|Federer: Serena may be the greatest of all-time|
|Copa Libertadores Review: Gremio top group, River and Flamengo draw|
|Celtics rebound with key game-five win over Cavs|
|Warriors duo Thompson, Iguodala questionable for game five|
|Suarez: Iniesta hard to replace at Barcelona|
|Slipper suspended after positive cocaine test|
|Cardinals´ Ozuna absent from line-up because he overslept|
|Ancelotti a ´real coup´ for Napoli as Insigne thanks Sarri|
|Johnston ´amazed´ to see Liverpool in Champions League final|
|Fearless Loftus-Cheek embraces England pressure|
|Butland shocked by Hart absence|
|It´s a football club – Klopp on choosing Liverpool over Man United|
|Emery appointed after secret vote, says Arsenal chief|
|Klopp used Sevilla loss to inspire European title tilt - Henderson|
|Lineker, Stoichkov, Zico - the stars who blazed a J-League trail for Iniesta|
|Golf not fame drives McIlroy|
|De Villiers tributes led by Du Plessis, Kallis and Tendulkar|
|Buttler ´maturity´ is just what England need, says Vaughan|
|Fit-again Wawrinka returns to winning ways|
|Toulouse take giant step towards Ligue 1 survival|
|Jets will not punish players for incurring anthem-related fines|
|F1 Raceweek: Hamilton and Bottas looking to build momentum - Monaco GP in numbers|
|Steelers´ Antonio Brown advises Le´Veon Bell to ´show up´|
|Stephens out in Nuremberg, Stosur wins Strasbourg final rematch|
|Clippers extend coach Rivers´ contract|
|Ancelotti ´thrilled´ by Serie A return with Napoli|
|Carlo´s Angels? Napoli boss poses for unusual photograph|
|Brady will attend Patriots mini-camp despite OTA absence - Kraft|
|World Cup hero, Champions League master - the best of Andres Iniesta|
|Heading to my new home - Iniesta drops massive Vissel Kobe hint|
|Neymar fitter than Brazil expected ahead of World Cup|
|Jardim, Jokanovic reject Chelsea speculation|
|Knight Riders rally dumps out Royals in IPL eliminator|
|Salah, Mane, Firmino trio could blow Madrid away, says Redknapp|
|Napoli appoint Ancelotti after Sarri departure|
|NFL stars must stand for national anthem if on field|
|Mascherano laments Romero injury blow|
|´Mr 360´ De Villiers retires after going full circle|
|Ronaldo already a Real Madrid legend like Di Stefano - Nacho|
|Pep or Pepe? The Spanish footsteps Emery could follow|
|Arizona, New Orleans land Super Bowls as NFL draft heads to Nashville|
|Sarri thanked by Napoli chief De Laurentiis amid Ancelotti reports|
|You never know! - Vettel and Hamilton joke about potential Ferrari link-up|
|It´s a silly question - Carrick insists Pogba has Man Utd future|
|Yates protects Giro lead as Viviani takes fourth stage win|