Teenager Jozy Altidore scored a hat-trick to give the United States a 3-0 win over Trinidad and Tobago while Costa Rica beat El Salvador 1-0 despite a penalty miss in Wednesday's other games.
After three games of the CONCACAF zone's final stage, the U.S. lead the six-team group with seven points, followed by Costa Rica on six and Honduras on four.
Mexico have three while El Salvador and Trinidad have two apiece.
The top three qualify for the 2010 World Cup and the fourth team will play off against the fifth side from South America for another place.
Mexico had relieved the pressure on beleaguered Eriksson by beating Costa Rica 2-0 on Saturday but the respite was short-lived.
Costly, who plays for English Championship (second division) side Birmingham City, slipped the ball between Guillermo Ochoa's legs in the 17th minute.
Pavon added a majestic second before halftime and Costly rifled home the third in the 79th minute. Nery Castillo pulled one back with a penalty before Mexico had Carlos Salcido sent off.
Costly scored both goals when Honduras beat Mexico 2-1 at the CONCACAF Gold Cup in 2007.
Pavon, 35, scored in 1996 when the Central Americans beat Mexico for the first time in a World Cup qualifier and notched a hat-trick in another qualifying win in 2001.
Ominously for Eriksson, coach Enrique Meza quit after that defeat.
Spain-based Altidore opened the scoring in the 13th minute in Nashville with a smart side-foot at the back-post after good work down the left from Brian Ching and Landon Donovan.
Donovan also set up the second in the 79th minute and the 19-year-old Altidore became the youngest player to score a hat-trick for the U.S. when his shot crept under the body of Clayton Ince in the 89th minute.
Costa Rica stayed on course for a third successive finals when a Walter Centeno header in the 69th minute beat El Salvador in San Jose.
In the first half, striker Andy Furtado had a penalty saved by goalkeeper Miguel Montes.
