M’Baye Niang scored a controversial goal to help Senegal make a winning start to their World Cup campaign with a 2-1 defeat of Poland.

The winger, who spent a brief loan spell at Watford in 2017, ran back onto the pitch after being treated for an injury to make the most of a sloppy back pass and put his side 2-0 up on the hour.

His goal drew vociferous complaints from the Poland players, but the effort, which saw Niang take the ball past Wojcicech Szczesny before turning into an empty net, stood after Niang had been given permission to come back on.

Senegal had taken the lead in fortuitous fashion when Idrissa Gueye’s shot deflected in off Thiago Cionek for an own goal.

Poland created precious little throughout the match before a 86th minute header from Grzegorz Krychowiak set up a frenetic finish.

The result leaves Senegal joint on three points with Japan at the top of Group H ahead of the two sides meeting on Sunday.