Manuel Pellegrini's substitutions came under fire from the West Ham crowd as they were held at home by Sheffield United.
Robert Snodgrass had put the Hammers into the lead a minute before half-time, but Pellegrini's decision to replace the midfielder late on was met with boos from the stands.
By contrast, Blades boss Chris Wilder sent on Lys Mousset from the bench and the French striker grabbed his second goal in two matches to secure a 1-1 draw.
Mousset's improvised far-post volley stretched West Ham's winless run to five outings, with the first signs of dissent towards the manager emanating from the home support.
"With three or four minutes to go in the game we wanted more players in the box so we could score the goal to decide the game," explained Pellegrini.
"Robert worked very hard, he played a very good game, but we needed fresh legs to try to score the second goal.
"Of course we are disappointed, we've dropped more points at home. We played a good game, we created chances, crosses, corners in the first half.
"We scored one goal and in the second half we had more opportunities but then they scored, and they defended very well."
It was a grudge match 12 years in the making at the London Stadium and, on the evidence of this game, and the season so far, both sides should at least be able to avoid a repeat of that bitter relegation battle of 2007.
A goal for Snoddy on his return to the side 👊 — West Ham United (@WestHam) October 26, 2019
This was the first Premier League meeting between the sides since Carlos Tevez's goals controversially helped West Ham avoid the drop at Sheffield United's expense.
The bitter Blades had remained outside the top flight until their return this summer, where they are now flourishing under Wilder.
"I've said all along that if the roles were reversed West Ham would have said the same about Sheffield United, and Sheffield United would say the same about West Ham," said Wilder.
"It's a talking point, but we want to make new memories for our supporters who have watched us through thin and thinner."
Mousset started among the substitutes despite his winner against Arsenal on Monday night.
Wilder added: "It's a difficult one but Lys is still not up to speed and it took a lot out of him on Monday.
"The easy thing is to keep the same team but I have to do the right thing. I thought he looked a threat when he came on and we were delighted he finished that opportunity.
"In the first half we were second to every ball. But our start to the second half was great, we dictated the game knowing we had to take a few more risks which we did.
"They had chances on the counter-attack and their manager will be disappointed not to put us to bed, but it was a deserved result."
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