Aleksandar Mitrovic's rich vein of form continued as he scored a first-half brace which helped Serbia to a 4-1 home win over Luxembourg in 2022 World Cup qualifying on Saturday that sent them top of Group A.
Serbia nosed ahead of Portugal on goal difference with both teams on 10 points from four games, four ahead of third-placed Luxembourg. Ireland and Azerbaijan have one point each after their 1-1 draw in Dublin.
It was another effervescent performance from Fulham striker Mitrovic who took his tally to seven goals in the qualifiers, firing Serbia ahead in the 22nd minute as he steered in a sublime pass by Sergej-Milinkovic Savic.
Mitrovic doubled Serbia's lead in the 35th as he powered a close-range header past visiting goalkeeper Anthony Moris after an inch-perfect cross from the left by Filip Kostic, who tormented his marker throughout the first half.
Serbia took their foot off the pedal after the break and were punished for some slack defending in the 77th minute as Olivier Thill pulled one back for Luxembourg with a rasping shot from 18 metres.
Substitute Dusan Vlahovic missed a sitter before a Maxime Chanot own goal restored Serbia's two-goal lead after Moris parried Mitrovic's header and the rebound ricocheted off the defender's foot over the line.
Luxembourg had striker Gerson Rodrigues sent off in stoppage time for a second yellow card before defender Nikola Milenkovic put the icing on the cake for Serbia with a fine header from another superb cross by Kostic.
Serbia next visit Ireland and Portugal are at Azerbaijan on Tuesday in what is shaping up to be a neck-to-neck race for an automatic berth at next year's tournament in Qatar.