"The game today was amazing," Lam said after the match in Hanoi's My Dinh Stadium Friday night.
"Looking at it from an optimistic point of view, I think 2-2 draw is a good result."
According to the away goal rule, Thailand now have the advantage. Vietnam will need to win or earn a draw of at least 3-3 in the second leg to win the championship, while Thailand will only need a goalless or 1-1 draw.
Lam said he believes in a triumphant result for Vietnam.
"Together we will certainly win the second leg," Lam said. "I and everyone else are confident."
The 2-2 draw on Friday ended Lam’s streak of six straight clean matches at AFF Cup 2022.
The 30-year-old successfully blocked all scoring attempts from Laos, Malaysia, Singapore, and Myanmar in the group stage, and Indonesia in the semifinals.
Vietnam opened the scoring on Friday night after center-back Que Ngoc Hai in an attack down the right flank crossed a great ball for Nguyen Tien Linh, who headed it in.
But early into the second half, Theerathon Bunmathan made a long pass for Poramet Aejwirai, who got past Ngoc Hai before finishing powerfully to equalize for Thailand.
Bunmathan contributed again to Thailand’s second goal 17 minutes later with a through ball for Sarach Yooyen, who finished cleanly to complete the comeback.
Vu Van Thanh equalized for Vietnam with a thunderous strike, four minutes after coming on as a substitution in the 88th minute.
Vietnam will leave for Thailand Saturday afternoon to prepare for the final’s second leg, which will be hosted on Thammasat Stadium at 7:30 p.m. Monday.