K.League leaders Pohang Steelers were held to a surprise 0-0 draw by bottom club Incheon United on Wednesday.
The reigning champions would have been confident of recording their third straight league win against a side who have picked up just one victory all season.
However, a shock was afoot at Sungui Arena Park, as Incheon held their own to earn a hard-fought point.
Pohang's slip-up did not prove costly, though, as second-placed Jeonbuk Motors also drew a blank in their 0-0 stalemate at Ulsan.
Those results mean it is as you were at the K.League's summit, with Pohang remaining two points clear of Jeonbuk.
Jeju United were the main beneficiaries of the top two dropping points, as they leapfrogged Jeonnam Dragons into third spot with a 2-0 home win over Ha Seok-ju's team.
Park Su-chang opened the scoring at the Jeju World Cup Stadium after 19 minutes, before Australian defender Aleksandar Jovanovic made sure of a valuable victory late on.
Elsewhere, an ill-tempered affair between Seoul and Sangju Sangmu in the capital ended 2-1 to the hosts.
Sangju received seven bookings throughout the game - including two for Yoo Ji-hun, who was sent off just before half-time - and went ahead 12 minutes after the interval courtesy of Kim Chang-hoon.
However, the visitors' numerical disadvantage soon started to show, and Mauricio Molina drew Seoul level with his first goal of the season 20 minutes from time.
Seoul made sure of all three points when Sergio Escudero popped up with a late winner.
In Wednesday's other action, Suwon Bluewings further boosted their Championship Round credentials with a 2-1 win at Busan, and Seongnam beat second-bottom Gyeongnam 1-0.
|Coach: Bong-Gil Kim|
for Hyo-Gyun Lee 68'
for Seok-Hyun Lee 72'
for Chun-Soo Lee 80'
|Lampard welcomes ´perfect´ NYCFC challenge|
|Shamrock Rovers 3 Progres Niederkorn 0: Waters at the double|
|Gerrard keen to emulate ´hero´ Beckham at Galaxy|
|UEFA Champions League Review: Red Imps make history, TNS breeze through|
|Ameobi extends Newcastle deal and heads for Cardiff|
|U.S. women celebrate World Cup victory with LA rally|
|Atletico agree Vietto deal|
|Silva appointed Olympiacos head coach|
|Presidential candidates unsure of Turan´s Barca switch|
|Toure keen to bounce back from ´disappointing´ campaign|
|El Salvador v Canada: Floro targets Gold Cup learning curve|
|Juve complete Zaza swoop|
|Costa Rica v Jamaica: Borges confident Wanchope´s men are ready|
|Marseille snare Sarr|
|Italy coach Conte to stand trial in match-fixing case|
|Castan keen to repay Roma´s faith|
|Rami thrilled to reunite with ´best coach´ Emery at Sevilla|
|Lusitans v West Ham: Tomkins seeks to silence minnows|
|Kagawa shines as Dortmund hit six in Japan|
|Alonso tips Gerrard for Galaxy glory|
|Firmino seeks self-improvement with Liverpool|
|Buffon bids farewell to Pirlo|
|Sterling named Europe´s ´most valuable´ young player|
|Casillas´ agent reveals Porto offer|
|Southampton bring in Martina|
|Dundee United accept Celtic´s Ciftci bid|
|McArthur pens new Palace deal|
|Bartomeu rules out Barca move for Pogba this year|
|Spurs have to be better now - Bentaleb|
|Milner expects central role|
|Micronesia thrashed again, this time 46-0|
|Marchisio: I cannot be Pirlo´s heir|
|Inter aiming for Champions League return - Icardi|
|UEFA Europa League Preview: Brondby and Slovan to protect handsome leads|
|Bentaleb pens new long-term deal at Tottenham|
|Barca agree Turan deal|
|FIFA bans Mayne-Nicholls|
|United States v Honduras: Klinsmann demands improvement ahead of Gold Cup opener|
|CONCACAF institutes extensive reforms in wake of FIFA corruption scandal|
|Mauri completes Milan move|
|City sign Turkey striker|
|Women´s World Cup final draws huge US TV ratings|
|My first Chelsea team better than current crop - Drogba|
|Bertrand set for lay-off after knee surgery|
|New five-year Juve deal for Marchisio|
|Allegri extends Juve contract|
|Koeman reiterates Alderweireld interest|
|Valencia bag Bakkali|
|New York City FC complete Pirlo capture|
|Panama v Haiti: Collat ready to challenge the best of CONCACAF|
|UEFA Champions League Preview: Harrison eyes TNS progression|
|FIFA sanctions Yemen for fielding ineligible player|
|Toulouse rubbish Ben Yedder exit reports|
|Mourinho ´knows what he´s doing´ with Falcao signing|
|Watford shell out club-record fee for Capoue|
|Braafheid signs Lazio extension|
|Nani finalises Fenerbahce move|
|Liverpool confirm O´Driscoll appointment|
|Liverpool have to start better - Lucas|
|USA simply too good - Sasaki|
|Portland Timbers 1 San Jose Earthquakes 0: Jewsbury wins it in stoppage time|
|No move yet for Van Persie|
|Lloyd wins Golden Ball, Silver Boot awards|
|Mascherano: I never grabbed Banega|
|Dunga requested Brazil not appeal Neymar´s suspension|
|United States 5 Japan 2: Lloyd stars with hat-trick|
|Fiorentina deny Inter criticism|
|Nani relishing Fenerbahce opportunity|