(Photo credit: Julia Kapros-Imagn Images)

Theo Corbeanu scored on a first-half penalty kick and Sean Johnson recorded his 108th career shutout to help Toronto FC record a stunning 1-0 victory over host San Diego FC on Wednesday night.

Corbeanu's 20th-minute goal held up as Toronto FC (5-11-6, 21 points) shut down the vaunted offense of San Diego FC. The Reds improved to 3-0-2 against Western Conference foes this season.

Johnson only needed to make one save for his sixth shutout of the season. His career count ranks fourth in MLS history.

San Diego FC (13-7-3, 42 points) remain in first place in the West despite the sluggish setback.

Toronto cautiously protected its late one-goal lead just four nights after allowing Atlanta United to score in the 11th minute of second-half stoppage time for a disappointing 1-1 tie.

Pablo Sisniega made one save for FC San Diego, who fell to 6-3-3 at home.

San Diego controlled the ball for two-thirds of the match and outshot Toronto 7-4 with all its shots coming in the second half. The Reds put two on target to San Diego's one.

High-powered San Diego FC holds the MLS lead with 46 goals.

But the club didn't take a single shot in the first half and didn't place a shot on target until the 71st minute when Chucky Lozano's right-footed shot was stopped by Johnson.

This was San Diego FC's first match since losing high-scoring Milan Iloski earlier this week. Iloski's loan was mutually terminated Tuesday when the two sides couldn't agree to contractual teams. Iloski's 10 goals were second most on the team.

Perhaps another reason for the slow offensive effort is that Lozano, one of three All-Stars on the squad, didn't enter the match until the 60th minute.

Lozano had a close-range opportunity in the 86th minute but his left-footed shot was blocked by Toronto defender Alonso Coello. The Reds then prevented any late-match drama while improving to 2-4-2 over their past eight matches.

Corbeanu fell in the box when he was kicked in the right knee by San Diego's Franco Negri in the 17th minute.

No foul was called at the time but replay officials signaled for a review and it was determined Corbeanu was fouled.

He stood at the spot in the 20th minute and delivered a right-footed boot into the top right corner of the net for his team-leading fifth goal of the season.

--Field Level Media