More than a quarter of West Midlands ambulances took longer than the target eight minutes to reach "life-threatening" emergencies last year - despite an £11.8 million cash boost.
The service missed its target of 75 per cent of category A calls responded to within the benchmark limit, but bosses today said its figures for the months following the injection of new funds showed a dramatic improvement.
West Midlands Ambulance Service trust received the extra money from health trusts across the region at the end of September, after blaming poor response times on a lack of funding.
Despite missing the annual target, the trust hit the 75 per cent benchmark for each of the last three months of 2009/10 - rising to 79 per cent in March. And trust chief executive, Anthony Marsh, admitted the service had endured a difficult year.
"There is no doubt that 2009/10 was a tough year, but what is very clear is the absolutely superb level of commitment from staff from right across the trust," he said.
"The trust has risen to numerous challenges over the year which all brought unprecedented increases in demand.
"These include a short heat wave, swine flu, and the coldest and snowiest winter for 30 years."
He said he was pleased with the service's improved results over recent months. "Working with our commissioners we were able to attract additional funding in the late autumn following an independent review which allowed the trust to deploy extra ambulance resources," he said.
"In the second six months of the year, the trust was one of the strongest performing ambulance organisations in the country. This is continuing, with the trust the best performing so far this year.
"Staff throughout the trust have worked incredibly hard to ensure patients continue to get the service they deserve. I am very proud of them and I hope the people of the region are too."
WMAS had previously revealed how it faced an increase in demand of 8.4 per cent last year, despite only being contracted for an increase two per cent. Primary care trusts in Walsall, Wolverhampton, Dudley and Sandwell were among 17 in the region that contributed the extra cash in September.
The money came on top of the organisation's £165 million annual budget.
Health trusts in the region had warned that if things did not improve after at least four performance notices, a warning would be served which gave them the power to withdraw funding altogether.
Bosses say that the extra cash was spent on extra staff, vehicles and training, all of which had helped improve response times.
And WMAS finance director Keith Wood said in October that a campaign was being launched to reduce the 'inappropriate use of ambulances' by the public.