Romford returned to the top of the Essex Senior League table after a 2-2 draw with landlords Barking.
Boro had made club history by winning their first five matches of the season in all competitions but had to come from behind to earn a share of the spoils at the Lawtech Stadium.
Bruno Gomes had early penalty claims turned down, before Aundre Spencer’s corner was converted by George Okoye to put Blues ahead on seven minutes.
Harry Girling kept out Junior Luke’s effort, with Gomes putting the rebound wide, before Kenedi Dariri was booked for kicking the ball away.
Martin Tuohy just failed to convert a left-wing cross on 26 minutes and Henry Mbassa was booked for pulling back debutant Sam Deering on the edge of the box.
Boro’s Scott Doe was shown a yellow card for kicking the ball away, before Jake Anderson made saves from Harvey Brown and Dariri towards the end of the half.
And the hosts made a double change at the break as Seedorf Mendes and Lee Hursit replaced Jamie Hursit and Jayden Sillcott-Brown.
And Gomes forced Girling into action within a minute of the restart, with Deering heading a Charlie Morris cross against the bar and then seeing Girling save another effort.
Gomes and Hursit had their names taken before Boro levelled on 62 minutes as Luke’s quick throw released Morris and his low cross was tapped in by Gomes.
Barking’s Brad Rowland was sin-binned and Tuohy booked by referee James Latham, before Boro took the lead on 73 minutes as Morris sent Deering through and he fired into the top corner.
But the visitors were back on terms eight minutes later when Daniel Okah headed home, before Boro’s Sonny Shilling and Blues keeper Girling were booked in stoppage time.
Blues boss Lee Benson saw red late on, with Gabriel Oloko dismissed in the eighth minute of injury time and Fahad Nyanja also booked before the final whistle.
Frenford fell to a 2-0 defeat at White Ensign after conceding a goal in each half.
Joe Gregory headed home at the near post to put Ensign in front, with Iyiola El-Ameen Adebayo doubling the lead with a left-footed finish.
Meanwhile, in Thurlow Nunn League Division One South, Hackney Wick romped to a 7-1 win at east London neighbours Clapton, with seven different goalscorers.
Having seen their under-18s beat Enfield Town 5-4 on penalties in the FA Youth Cup after a 2-2 draw the previous evening, Wick’s first team opened the scoring early on.
Benson Osejindu, Piotr Maslowski and Victory Akam also struck to put Wick 4-0 up at the break and Sebaihi Mohamed added a fifth midway through the second half with his first goal for the club, before Tyler Houston-Taylor grabbed an 82nd-minute reply for the hosts.
65 @ClaptonFootball 0 @hackneywickf 5 Sebaihi Mohamed finally scores his first goal for the club pic.twitter.com/XphUNjz8lm
— Hackney Wick FC (@HackneyWickFC) August 16, 2023
Solaiman Nakmouche converted Wick’s sixth from the penalty spot in the last minute of normal time, with Clifford Newby Harris making it a magnificent seven in stoppage time.
The heavy defeat leaves Clapton bottom of the table, with Tower Hamlets also suffering a fourth successive loss as they slipped to a 3-2 home defeat against Park View at Mile End Stadium.
Solomon Asomoh was on target once again for Kiernan Hughes-Mason’s side, with Junior Baker also hitting the net.