Western Conference top seeds St. Louis City suffered a shock 4-1 defeat at home to Midwest rivals Sporting Kansas City in the opening game of their best-of-three series in the MLS playoffs on Sunday.

Expansion club St. Louis defied all expectations in their debut season but came crashing down to earth in game one of their first-round series.

Logan Ndenbe fired Kansas City ahead with a thundering left-foot drive in the 27th minute but the lead lasted just a minute as St. Louis defender Tim Parker levelled from close range after a corner.

But Sporting, a wildcard qualifier, continued to attack with purpose and restored their advantage through French midfielder Remi Walker, who drilled home a low shot from the edge of the box.

Three minutes later and it was 3-1 for the visitors with Ethiopian-born Israeli international Gadi Kinda scoring a wonderful solo strike, bursting towards the box before unleashing an unstoppable blast from 25 yards.

Any hope St. Louis had of turning the game around ended in the 61st minute when Hungarian Daniel Salloi stole in at the back post to turn in the fourth.

The teams meet again in game two on November 5 in Kansas City.

Argentine Alvaro Barreal scored twice as FC Cincinnati, the overall top seed, made a convincing start to their post-season push with a 3-0 win over New York Red Bulls in game one on Sunday.

The 23-year-old Barreal, one of a number of talented South Americans now plying their trade in MLS, opened the scoring for Cincinnati in the 23rd minute, running onto a perfectly weighted through ball from Junior Moreno and finding the bottom corner.

Another Argentine, Luciano Acosta, doubled the lead for Cincinnati in the 35th minute when a poor back-header from Red Bulls defender Andres Reyes forced goalkeeper Carlos Coronel to rush out of the box to clear.

But the ball fell to playmaker Acosta, who, spotting the 'keeper off his line, beat him with a lofted chip from over 30 yards out.

New York pushed hard in search of a way back into the game but the match was put beyond them by Arreal in the 89th minute.

Acosta fed his compatriot with a chip into the box and Arreal's deft first touch set up his own volley, which flew past Coronel. The pair will face off again in New York on Saturday.

Amine Bassi struck a 79th-minute winner as the Houston Dynamo beat Real Salt Lake 2-1 in their first match.

French-born midfielder Bassi pounced on a loose ball in the box and slotted home after Griffin Dorsey's low effort had been pushed out by Zac MacMath.

Houston, the fourth seed in the Western Conference, dominated fifth-seeded RSL from the outset, pinning their opponent back in the opening stages.

The Dynamo grabbed the lead in the 22nd minute through Mexico international Hector Herrera, who collected a cushioned header from Adelberto Carrasquilla and fired home from the edge of the box.

The goal forced RSL into a more positive approach and Costa Rican wing-back Bryan Oviedo went close with a shot that was cleared off the line by Houston's Brazilian defender Micael.

Diego Luna curled a shot wide for the visitors just before the break and that was a sign of things to come from Salt Lake.

It was a superb counter-attack 10 minutes after the interval that brought RSL level, with Andres Gomez driving from deep in his own half before squaring to Luca, who fired home.

But Houston, the US Open Cup winners, responded strongly and former Nancy midfielder Bassi's decisive strike gave the Dynamo the series advantage ahead of their November 6 meeting in Salt Lake.

"A playoff win -- it's hard to get 'em, believe me," Houston coach Ben Olsen said.

"You see why because you're going against opponents now that are cagey, experienced, you're going against a coach that has been in these situations many times and has had success. These are what playoff games look like."

The first round continues on Monday with Orlando City hosting Nashville in the East while in the West the Seattle Sounders face Dallas.