Both sides were forced to settle for a share of the spoils at St. James' Park after a catalogue of missed chances means qualification to the next round is still wide open
Mexico and South Korea were forced to settle for a share of the spoils in a lacklustre Group B opener.
The Koreans were the more dominant of the two sides but, with the exception of skipper Koo Jacheol's glancing header, were restricted to long-range efforts by Tena Luis Fernando's side in a game that never threatened to spring into life.
Mexico came close to snatching all three points in the dying seconds, as second-half substitutes Giovanni dos Santos and Raul Jimenez both spurned gilt-edged opportunities.
It was South Korea who began on the front foot with the lively Park Chu- Young carving open their first real effort on target after 16 minutes, but the Arsenal man's free kick cannoned off the wall and out for a throw-in.
Lekhwiya SC midfielder Nam Teahee found himself in space soon after, but his long-range effort drifted harmlessly over the bar before half-hearted Korean penalty shouts were waved away when Park Jong-Woo was felled in the box.
Mexico appeared content to defend deep inside their own half, but they had restricted Hong Myung Bo's side to only a smattering of corners in a fairly drab opening 45 minutes.
It hadn't been the best advert for Olympic football so far, but both sets of fans were doing their best to make St James' Park a familiar cauldron of noise as the competitors searched for that elusive opener in the second half.
And just four minutes after the restart, normal service resumed as Kim Bo-Kyung's left-footed effort curled narrowly wide of the upright. Skipper Koo Ja-Cheol was the next to spurn a great opportunity for the Koreans, as he latched onto Chu-Young's deft flick-on, but he could only angle his volley the wrong side of the crossbar.
It was once again all one-way traffic, but for all of their toil and endeavour, the Koreans couldn't break the deadlock and they nearly paid for it three minutes later when Javier Aquino's powerful drive was beaten away for a corner.
The game was finally beginning to open up and Herrera was booked just shy of the hour mark after he clipped the galloping Kim Bo-Kyung when the Cerezo Osaka man burst through on the break. Mexico's goal was living a charmed life and Nam Tea-Hee was next to try his luck, when he cut inside in the 64th minute and sent a dipping right-footed effort agonisingly wide.
The longer the game went on, it looked as though just one goal would win it and predictably, it was Mexico who would twist first when Spurs forward Dos Santos was thrown on in place of the largely ineffective Oribe Peralta to try and snatch the victory.
And within just minutes of his introduction, the Korean defence were left back-pedalling as the 23-year-old drove forward and his shot was deflected wide. From the ensuing corner, Mexico should have opened the scoring when Marco Fabian swung wildly at a loose ball from just seven yards.
It would have been hugely undeserved, but it was probably the best opportunity of the match so far until Ja-Kcheol glanced Bo-Kyung's cross wide of the mark when he really should have tested Corona with just 10 minutes remaining.
Mexico themselves had a chance to snatch it right at the death, but Dos Santos' flying volley skewed narrowly wide when he should have scored and then substitute Jimenez clipped the upright when he raced clean through.