Williams' Formula One driver Alex Albon suffered "respiratory failure" and was left on a ventilator following complications from surgery on his appendix.
Albon, 26, was ruled out of the Italian Grand Prix in Monza with appendicitis on Saturday morning, before being transferred to nearby San Gerardo Hospital for treatment.
The Thai driver underwent surgery but then ended up in intensive care after he required assistance breathing.
Williams say Albon was "removed from mechanical ventilation" on Sunday and is expected to remain in hospital on Monday.
A statement from the British team said: "Following surgery, Alex suffered with unexpected post-operative anaesthetic complications which led to respiratory failure, a known but uncommon complication. He was re-intubated and transferred to intensive care for support.
"He made excellent progress overnight and was able to be removed from mechanical ventilation yesterday morning. He has now been transferred to a general ward and is expected to return home tomorrow."
London-born Albon, who races under the Thai flag because of his mother Kankamol's nationality, took part in practice in Monza on Friday.
But he fell unwell on Saturday morning and was replaced by the team's reserve driver Nyck de Vries, who finished an impressive ninth to score points on his F1 debut.
Albon spent last year on the sidelines after he was dropped by Red Bull.
But he has steadily impressed since his transfer to Williams, scoring his first point for the British team at the Australian Grand Prix in April, with two further top-10 finishes in Miami and Belgium.