MLS Golden Boot winner Valentin Castellanos scored as New York City clinched a spot in the Eastern Conference semi-finals with a 2-0 home win over Atlanta United on Sunday.

Castellanos, who netted 17 regular-season goals, opened the scoring in 49th minute with a miscued volley which bounced in fortunately over Atlanta goalkeeper Brad Guzan.

Alexander Callens doubled New York City's lead four minutes later, heading in unmarked from close range after Guzan tipped Maxi Moralez's effort on to the frame of the post.

Atlanta defender Alan Franco was sent off late for dissent to rub salt into the wounds, as New York City secured a fifth semi-final berth in the past six seasons.

New York City will next play Eastern Conference top seed and Supporter's Shield winners New England Revolution.

Sebastian Blanco netted a second-half double as Portland Timbers came from behind to beat Minnesota United 3-1, clinching four consecutive wins and a Western Conference semi-final date with Colorado Rapids.

Franco Fragapane gave Minnesota an 11th-minute lead, but Portland rallied with Larrys Mabiala heading in the equaliser before half-time.

Blanco rifled in a low drive early in the second half before opening a two-goal lead with a spectacular 66th-minute long-range strike.

Portland Timbers upset Western Conference leaders Seattle Sounders to win Sunday's derby 2-0 after two defensive blunders to round out the rivalry week in the MLS.

Second-half strikes from Sebastian Blanco and Felipe Mora earned the Timbers the points, ending Seattle's three-game winning run and ensuring they missed the chance to extend their lead to five points.

Portland had failed to win in their past three games, with the result lifting them from 10th in the west, up to sixth.

Blanco's goal was particularly special, having torn his anterior cruciate ligament (ACL) at the same venue nearly a year ago.

Mora pounced on a poor Yeimar Gomez Andrade back pass, swooping in and setting up Blanco for a 58th-minute tap-in.

Timbers goalkeeper Steve Clark made numerous saves, including from a rocket 61st-minute Joao Paulo volley, before Mora capitalised on an error from Sounders keeper Stefan Cleveland, sealing the points with a classy lob in the fifth minute of stoppage time.

Eight goals were scored in an entertaining Texas derby as Dallas got the better of Austin 5-3 – teenager Ricardo Pepi and Jesus Ferreira both netting braces for the winners.

Dallas raced to a 4-1 lead at the break before Jader Obrian added a fifth shortly after half-time, with Austin pulling goals back via Diego Fagundez and Alexander Ring as Ferreira hit the post late in pursuit of a hat-trick.

Pepi, who turned 18 in January and last month became the youngest player in MLS history to score a hat-trick, has netted 11 times this season for Dallas.

Meanwhile, Vancouver Whitecaps continued their resurgence under interim head coach Vanni Sartini with a 4-1 rout of Real Salt Lake.

The Whitecaps piled on three goals inside 16 second-half minutes after Marcelo Silva's own goal had given them a 1-0 lead at the interval.

Cristian Dajome was dangerous down the right flank, as Brian White, Ryan Gauld and Florian Jungwirth netted before Anderson Julio's consolation for RSL.