While Donald Trump’s advisers have publicly praised his performance in the first presidential debate, The New York Times reported Wednesday that they have privately lamented the real estate mogul’s missed opportunities to attack Hillary Clinton and palpable loss of steam as the 90-minute event wore on.

Seven campaign aides and advisors who spoke to the Times on condition of anonymity attributed the subpar performance to Trump’s lack of focus in prep meetings, unwillingness to practice using a podium or doing mock debates, and reliance on advisers like retired Army general Michael Flynn, who has no experience with presidential debates.

While Trump has touted his victory in a spate of unscientific online polls, both conservative and liberal political analysts have said Trump’s lack of preparation was readily apparent during Monday’s face-off, allowing Clinton to steer the conversation and get under his skin. Despite engaging in an extended back-and-forth with moderator Lester Holt in which he falsely insisted he never supported the Iraq War, randomly insulting comedian Rosie O’Donnell, and bragging about the fact that he didn’t pay taxes, Trump left the debate confident, telling reporters the questions were “very fair.”

By the next morning, Trump was lashing out at the “unfair” questions posed by Holt and biased media coverage of the debate, introducing complaints about a faulty microphone to help explain his performance.

Trump said he may “hit her harder” in the next debate on Oct. 9 in St. Louis, Missouri, which will be a town hall format where undecided voters will be allowed to ask the candidates questions.

According to the Times, advisers want Trump to practice debating in this format, address the nuances of going head-to-head with a female candidate, and hone his attacks on Clinton’s vulnerabilities. They reportedly remain concerned that he will follow through.