The New England Revolution claimed a 2-1 victory over Sporting Kansas City in the first leg of their MLS Eastern Conference semi-final showdown.
Former St Mirren and Crystal Palace midfielder Andy Dorman opened the scoring for the Revolution, who are appearing in the post-season for the first time since 2009, in the 55th minute and Kelyn Rowe made it 2-0 in the 67th.
Aurelien Collin pulled a goal back shortly after Rowe struck to boost Sporting's hopes ahead of the second leg at Sporting Park on Wednesday.
The Portland Timbers took control of their Western Conference semi-final against Seattle Sounders with a 2-1 victory in the away leg.
Ryan Johnson headed the Timbers, who are making their first post-season appearance, into an early lead before Darlington Nagbe doubled their advantage midway through the second half.
Osvaldo Alonso gave the Timbers some food for thought before their home leg on Wednesday when he replied for the Sounders in the 90th minute.