Portugal scored twice in the last two minutes on its way to a flattering 3-0 win over Senegal Sunday which lifted it atop Group C at the FIFA Under-20 World Cup in New Zealand.
Late goals in Hamilton by Andre Silva and Nuno Santos gave Portugal the group lead on goal difference from Colombia which had earlier beaten Qatar 1-0 at the same Waikato Stadium.
Portugal emphasized its strong claims to the Under-20 title, which it won in both 1989 and 1991, when it scored its opening goal through Gelson Martins after only 26 seconds - the fourth-fastest goal in the tournament's history.
Goalkeeper Ibrahima Sy kept Senegal in the match until the final minutes when Silva and Santos made the match safe for the two-time champion.
Gaston Pereiro scored the winning goal in the 56th minute as 2013 finalists Uruguay beat Serbia 1-0 at Otago Stadium in Dunedin.
Serbia was the dominant team for much of the match but fell behind against the run of play when Facundo Castro provided the looping, right-footed cross which Pereiro headed home.
The Serbs continued to apply pressure but Uruguay was able to hold out for a win which left them just behind Mali in Group D.
Ten-man Mali beat nine-man Mexico 2-0 in a match which became spiteful in the second half to go atop the group in the first major upset of the tournament in Dunedin.
Mali was forced to defend for much of the first half and seemed likely to be further stretched when Hamidou Maiga was shown a red card in the 56th for a clumsy tackle on Hirving Lozano.
But Mexico went from being a man up to a man down in the space of two minutes, when Diego Gama was sent off for an off-the-ball incident in the 66th and Oscar Bernal received a second yellow card for his challenge on Souleymane Diarra in the 68th.
Mali quickly capitalized on its numerical advantage, scoring in the 76th through Adama Traore who headed home Youssouf Kone's free-kick. Mali sealed the game three minutes later when Dieudonne Gbakle worked a one-two with Alassane Diallo, who beat two defenders and sent his low shot just inside the far post.
''We need to critically analyze what happened in this game,'' Mexico coach Sergio Almaguer said. ''As a team, we need to play with a bit more intelligence and focus.
''We had chances throughout the match but failed to take them. This was only the first match, though, so we need to look forward because we've still got more games to come.''
Mali coach Fanyeri Diarra said the early win lifted pressure from his team.
''I'm amazed by the great shape my players are in physically,'' he said. ''They're up to the task even though they're coming to the end of the regular season at club level.
''In a tournament like this one, the first match is vital. Leaving here with three points means the lads will be under much less pressure going into our second game on Wednesday against Serbia.''
Earlier, Colombia beat Qatar 1-0 in Group C, scoring in the 24th through Joao Rodriguez, then holding out a strong resurgence from the Asian champions throughout the second half.
After a slow start, Colombia created a classy goal when Santos Borre laid the ball into the path of Rodriguez who placed his shot between the legs of Yousof Hassan.
Rodriguez might have had a first half hat trick as Colombia continued to dominate. He blasted a shot straight at Hassan after a tight turn which eluded the defense, then failed to take advantage of a defensive mix-up created by Jeison Angulo's accurate pass.
Qatar came out strongly in the second half with Amoez Ali and Jassim Al Jalab combining in two raids which almost produced an equalizer. They continued to press through the dying stages of the match but Colombia held on to take the three points.
''We showed clearer thinking in the first half,'' Colombia coach Carlos Restrepo said. ''In the second half Qatar reacted and we lost control of possession, so we were unable to threaten their box much.
''I'm very pleased because it was our opening game of the tournament and at times the team displayed a lot of character in their play up against a very strong defensive unit.''