Senegal joined Japan on three points at the top of Group H as they opened their 2018 FIFA World Cup campaign with a 2-1 victory over Poland at Moscow's Spartak Stadium on Tuesday.
Thiago Cionek's 37th-minute own goal put the African side ahead before a calamity of errors from Grzegorz Krychowiak and Wojciech Szczesny allowed Mbaye Niang to nip in for the second just after the hour.
Krychowiak slightly made amends with a late goal of his own as he headed home Kamil Grosicki's cross, but Senegal held on for a potentially vital victory.
Poland joined Colombia at the bottom of the standings in Group H following a shock defeat for Los Cafeteros earlier in the day.
Lewandowski Needs to Improve to Avoid UEFA Euro 2016 Repeat
Robert Lewandowski did not score a goal at Euro 2016 until his fifth appearance in the quarter-finals.
Based on Tuesday's evidence, Poland are unlikely to make it to the knockout rounds at the 2018 World Cup and the Bayern Munich man may endure another barren group stage.
There were extenuating circumstances for his inability to get much of the ball against Senegal, he was well marked and Poland's ambition was lacking.
And he did at least work the goalkeeper with a free-kick in the second half, unlike the early stages of the Euros:
But, as one of the most lethal strikers in Europe, Lewandowksi needs to make more of an impact at major tournaments, and if he is not given the ball he needs to go in search of it.
Senegal Emerge As Africa's Best at World Cup
It's not been the best of starts to Russia 2018 for the African nations, and Senegal went into Tuesday's clash with the pressure of a confederation, as well as a country, on their backs, per BBC Sport's John Bennett:
The current Lions of Teranga side have the quality in their ranks, and the favour of the draw, to match the heroics of their only previous World Cup side, the 2002 outfit who made it to the quarter-finals.
Aliou Cisse's men have given themselves an excellent chance of getting out of Group H by picking up all three points against Poland.
It was hardly a fluent display. Senegal's opener came via a rank Cionek deflection from a long-range Gueye effort, while Poland were architects of their own downfall—in setting up the second from Niang, Krychowiak was particularly culpable for an aimless back pass.
But Senegal know they have more to give and will no doubt now have designs on topping Group H.
Poland's No. 8 FIFA Ranking Will not Strike Fear into Future Opponents
Going into the tournament it always seemed as though Poland were in something of a false position at No. 8 in the FIFA rankings, ahead of Spain, Uruguay and Mexico, among others.
But their opening performance against Senegal suggested it is nothing less than a gross anomaly.
Their goal came from an excellent header from Krychowiak, but it was too late in the 86th minute.
Poland's reaction to going 2-0 behind was perhaps even more egregious than the way they conceded.
There was no urgency going forward and it almost seemed they didn't know the gravity of the situation they were in, hardly a hallmark of a top-10 side.
Colombia were hamstrung by an early sending off in their defeat to Japan, but showed plenty of resilience and flair, while the Samurai Blue will take huge confidence from their opening win.
It would be little surprise in Group H if the top-ranked side were to end up bottom of the standings after all the matches have been played.
Both teams now have a five-day break until their second Group H games on Sunday, when Senegal take on Japan in Yekaterinburg and Poland face Colombia in Kazan.