In a tense four-set contest, Puerto Rico eventually ran out 25-22, 25-19, 25-27, 25-23 winners.

Puerto Rico scored 54 kills to Mexico's 48 and six aces to Mexico's two.

Outside hitter Marie Victoria led the Puerto Rican scorers with 16 points, all in kills, and was supported by middle blocker Neira Ortiz and outside hitter Stephanie Enright, who scored 11 points each.

Mexican Samantha Bricio led all scorers with 20 points.

In the other quarter-final, the US defeated Costa Rica in convincing fashion.

Winning the first set in 25-11, the Olympic champions sauntered to an easy 25-11, 25-17, 25-10 victory.

The US dominated in blocks - winning 11 points to Costa Rica's three - and aces - seven to one.

Opposite hitter Veronica Perry led all scorers with 14 points, consisting of 10 kills, one block and three aces.

"I am happy with the group of players that came in that gave us a boost," US coach Joseph Trinsey said. 

"For the semi-finals, we have to sustain consistency, in every match we’ve actually come out very strong and we’ve been on it from the beginning but we need to sustain it for the entire match".

Costa Rica captain Mariana Rodríguez said: "We’ve been training well, nevertheless we didn’t perform as we expected.

"We know that the United States is an excellent team and our execution is messy. 

"We had some inconsistencies in receiving, which ruins our scheme. 

"This match gives us a better picture of what to practice on and improve."

Tomorrow's semi-finals see Canada face Puerto Rico and the Dominican Republic play the US.

The winners will secure a place in the NORCECA Continental Championship final and one of two spots in next year's International Volleyball Federation World Championship.