The Welsh Ambulance Service has claimed its current performance is the best in its history after it hit response targets for the second month running.
The service is on track to beat its response targets for May
Figures for April reveal the service reached 66.3% of life threatening emergencies inside eight minutes.
It is the second month running the service has beaten the 60% target set by the Welsh Assembly Government.
The service was branded "appalling" and "unacceptable" in a report by a committee of AMs in March.
The improvements are down to modernisation and staff commitment, said chief executive Alan Murray.
Mr Murray, who became chief executive last August, said a modernisation plan entitled Time to Make a Difference - drawn up in consultation with staff, unions and other healthcare providers - would further improve the service.
At the time of his appointment, the figure for calls reached in eight minutes was 55.4%.
A series of measures, including using GPs in control centres and more use of rapid response vehicles, have since been introduced.
Mr Murray said the improvements were aided by staff commitment
Mr Murray said the Welsh Ambulance Services Trust was a very different organisation from the one heavily criticised in the reports of the Auditor General, the Healthcare Inspectorate Wales and the Wales Audit Office.
"All those reports pointed out there was good reason to be optimistic about the future and their faith is being borne out by the improvement in our performance," he said.
"Our modernisation plan is a patient care-led strategy although there is obviously a correlation between the speed with which ambulances arrive and good patient outcomes."
The service's previous best performance record in its nine year history was set in March 2004 when the figure reached 63.03%.
The service also said it was on track to beat its targets for May.
Its response figure for February was as low 49.8% but this improved to 60.8% in March.
As a result of the improved performance, the service has claimed it reaches an extra 70 people suffering life-threatening emergencies within the target time every week.
It follows a difficult period for the service, which had appealed to people living in Cardiff and the Vale of Glamorgan to only dial 999 in a life-threatening emergency a few months ago because of the pressure it was under.
The Welsh Ambulance Service was also rocked by changes in management and a public inquiry ordered by assembly members into its poor performance.
But even the traditionally poorest performing region - the south east - posted good response times over the months of March and April, said the service. In April, their time topped the league reaching 68.1%.
Nigel Rees, a paramedic supervisor in Swansea, said the number of rapid response vehicles had doubled in the last six months which had made a difference.
"The cars get to the 999 call roughly three to four minutes before the ambulance, or it's supposed to anyway, and that means that treatment can start that much sooner so the patient will benefit.
Paramedic supervisor Nigel Rees said morale has improved
"We had a problem with our meal break situation before whereas now they have improved. So generally morale has improved but it's still a very stressful job."
Trust chairman Stuart Fletcher said the board was "delighted" with the changes and pointed out that the record figures came despite the service dealing with more cases than ever.
The drive for improved performance had been spearheaded by director of ambulance services Mike Cassidy who also took personal control of south east region.
He praised staff for responding to calls more quickly.
"We are not pursuing these response times for their own sake but because it leads to a better chance of survival for patients," he said.