Poland fired a second successive blank in the absence of captain Robert Lewandowski as Mexico eased to a 1-0 friendly win in Gdansk on Monday.
Adam Nawalka's men piled on 13 goals over their final three World Cup qualifying matches but, with Lewandowski resting an injured thigh, were held to a 0-0 home draw by Uruguay on Friday.
And further questions over the team's attacking depth were raised by a second toothless display.
Raul Jimenez's 13th minute goal proved the difference in a muted affair as both managers looked to experiment with their options for the World Cup.
Poland had caught the eye in collecting eight wins from 10 in qualifying, but it was El Tri who finished the international window the happier of the two teams as they registered a first clean sheet in five matches.
Match-winner Jimenez spurned an early chance to open the scoring when he headed straight at Wojciech Szczesny from Jonathan dos Santos' cross, but the striker made no mistake with his next opportunity.
Javier Aquino's dribble into the area ricocheted off a defender and broke kindly for the Benfica man, who lashed a thumping first-time strike into the top left corner.
Poland saw a goalmouth scramble come to nothing on 20 minutes and were forced to wait until after the half-hour to create a clear sight on goal, only for Piotr Zielinski to spray his half-volley harmlessly over the bar.
Jesus Corona was finally forced into his first real save shortly before the hour as Maciej Rybus attempted to sneak a low finish inside the near post.
But it was Mexico who came closest to a second as substitute Oribe Peralta twice tried his luck, the misses ultimately mattering little in a comfortable victory for the visitors.
