Regardless, Hà Nội announced that the club's leadership had accepted Nghiêm's resignation on Sunday.
Nghiêm leaves his side in the sixth position in the V.League 1 with 10 points after six matches, a disappointing start to a season in which the club were widely tipped to return to the top of local football.
Last season was also a struggle for Hà Nội as the side finished second after winning the title in 2019.
In his more than five seasons in charge, Nghiêm helped the team win the V.League 1 in 2016, 2018 and 2019; the National Cup in 2019 and 2020: the National Super Cup in 2018, 2019 and 2020; as well as enter the AFC Cup's ASEAN Zonal finals in 2019.
The team moved quickly to announce a replacement coach before their next match against local rivals Viettel in the Hà Nội derby on Wednesday.
Former Việt Nam national team coach Hoàng Văn Phúc will take charge of the team on a temporary basis, an announcement on the official Hà Nội FC Facebook page said.
Phúc has worked as a youth coach for Hà Nội after many years in charge of Quảng Nam. In addition to the V.League 1 title in 2017 with Quảng Nam, Phúc coached the national team and U23 national team in 2013.
The country's most successful team in recent years are facing an injury crisis at present, with star midfielder Đỗ Hùng Dũng out for the long-term, while Brazilian forwards Geovane Magno and Bruno Cunha both missed Friday's match due to injures. — VNS