Unsurprisingly, two teams that have found it hard to score at this U-20 World Cup found it hard to score against each other.
Ultimately, a second yellow card for Alioune Gueye tipped the match Mexico's way. Playing 10 men for the final 20 minutes, and with fresh legs on the field for the last 10, El Tri managed to find the net in the 89th minute thanks to the poacher's instincts of Ronaldo Cisneros.
The last-gasp, 1-0 win seemed about right - most observers would have predicted a game decided by a single goal or penalties.
Senegal was made to regret missing a near-open goal in the first half, but neither team managed to alter the perception that their form and finishing isn't really what one might expect of a World Cup quarterfinalist, even at the U-20 level.
Mexico advances to play England in the last eight. On current form, that could be an almighty mismatch. Senegal might be grateful for avoiding a run against what seems to be one of the better teams in the tournament. And El Tri will need be a lot better than it has been so far in this competition if it is to avoid embarrassment in the next round.