Port rallied twice to salvage a 2-2 draw with visiting Chonburi in a Thai League 1 battle on Saturday night but the result did little to ease pressure on home team coach Jadet Meelarp.
Port, who led the league until a few weeks ago, have now gone five matches without a win and are down to fifth spot in the table.
All the goals were scored in an entertaining first half with Worachit Kanitsribumphen netting the first for the Sharks in the eighth minute. Port took 10 minutes to level the score through Siwakorn Jakkuprasart.
Caion Herlison's spectacular curler from the top of the box on 42 minutes proved in vain as Sergio Suarez tapped home from close range to pull off another tie for Port in the last minute before half-time.
A last-gasp goal by William Henrique gave Chiang Rai United a narrow 1-0 home win over Chainat on Saturday night.
The Beetles are now tied on 33 points with defending champions Buriram United, who face a tricky assignment at PT Prachuap tonight.
Ratchaburi squandered a two-goal advantage to settle for one point after a spine-chilling 3-3 draw at Nakhon Ratchasima last night.
Ratchaburi went ahead in the 12th minute when Lossemy Karaboue scored. Leandro Assumpcao put the hosts on equal footing before Steeven Longil had a brace for the visitors.
Nakhon Ratchasima got two injury-time goals from Bernard Henri and Amadou Ouattara to deny Ratchaburi a victory.
Meanwhile, hosts Chiangmai held 10-man SCG Muang Thong United to a 1-1 draw in a match which saw social media go into overdrive on Friday night.
The netizens criticised the home team for their physical approach and castigated match referee Warin Satsadi for a below-par performance with some even asking the Football Association of Thailand to "re-educate" its referees.
Chiangmai, playing their last match at Chiang Mai 700th Anniversary Stadium which will now be closed for renovation for the AFC U23 Championship next year, went ahead shortly before the 30-minute mark when Chotipat Poomkaew's shot brushed off the post before ending up in the net.
A few minutes later Kirins defender Adisorn Promrak was sent off for a rough tackle on Giornata Vertura, leaving the former champions a man short on the pitch for almost an hour.
Muang Thong United were rescued by substitute Sanukran Thinjomn who delivered the equaliser with a long shot six minutes before time.
Muang Thong coach Alexandre Gama said: "We were unlucky to have only 10 men left and that forced us to make some tactical changes. We created several chances and I am quite pleased with the draw."