Kuala Lumpur: Malaysia will go into the second leg of their AFF Mitsubishi Electric Cup 2022 semi-final on the front foot after edging reigning champions Thailand 1-0 in an eventful first leg at the Bukit Jalil National Stadium on Saturday.

Malaysia found the all-important goal against the run of play in the 11th minute as Faisal Halim struck his fourth of the tournament to celebrate his 25th birthday in style with the 59,000 crowd watching from the stands.

The second half witnessed Malaysia having a goal ruled out while Thailand’s appeal for a late penalty was turned down too, meaning the six-time champions tasted their first defeat in the AFF Championship since 2016.

Malaysia head coach Kim Pan-gon gave Lee Tuck a start in the last four clash as he replaced Mukhairi Ajmal while Thailand fielded the same 11 that defeated Cambodia 3-1 in their final group outing with Peeradon Chamratsamee starting up front alongside Teerasil Dangda.

The defending champions exerted pressure on the hosts straight from the kick-off. Pansa Hemviboon almost gave the Thais a lead just five minutes in as Ekanit Panya’s cross from a short corner was headed wide by the unmarked Thai centre-back with the goal gaping.

Four minutes later, Sarach Yooyen’s delivery seemed destined for Teerasil's head, but Malaysia goalkeeper Syihan Hazmi came off his line to punch the cross away from danger.

But it would be Kim’s side who would break the deadlock against the run of play in the 11th minute. Sharul Nazeem played a hopeful long ball into the box from the halfway line and Ruventhiran Vengadesan headed it across the goal for Faisal to score his fourth goal of the tournament through the legs of Thai goalkeeper Kittipong Phuthawchueak.

Teerasil and Bordin Phala saw their attempts flash wide of the goal as Thailand looked for a way back before Theerathon played a delightful ball over the Malaysian defence in the 27th minute that was met by Peeradon, but the Buriram United man’s attempt, under pressure from Syihan, was off target.

The Harimau Malaya almost made it 2-0 on the break the very next minute as Faisal split the Thai defence as his pass sent Quentin Cheng through on goal, but the right-back saw his effort sail over Kittipong’s goal.

The War Elephants continued to hog possession for the remainder of the first half, but hardly gave any trouble to the Malaysian defence. But Polking’s men came the closest to scoring in Kuala Lumpur straight after the start of the second half.

Teerasil did well to get in front of Sharul to head the Suphanan Bureerat cross, but only against the woodwork. Then, in the 52nd minute, Suphanan’s shot from range brushed the roof of the goal on its way out.

Thailand custodian Kittipong found himself in no man’s land in the 55th minute as he came out to punch Tuck’s free-kick. But the ball instead bounced off Dominic Tan’s back into the goal only for the referee to disallow the goal for a foul in the build-up.

Syihan then had to advance from his line to deny Ekanit in the 63rd minute before Pansa had a second gilt-edged chance to score three minutes later, but the result was the same as his header lacked accuracy.

Thailand had shouts for a penalty waved away in the 84th minute after Bordin went down inside the box under the challenge of substitute Nur Shamie, but Malaysia held on for the one-goal advantage ahead of second leg at the Thammasat Stadium in Bangkok on Tuesday.