SHANGHAI (Reuters) - A frustrated Felipe Massa was left ruing a pitstop blunder by his Williams team that left him out of the points in Sunday's Chinese Formula One Grand Prix.
The Brazilian had qualified in a season best sixth on Saturday and was racing the top five cars when he came into the pits for fresh tyres at the end of lap 10.
Confusion reigned in the Williams pit-box, however, with mechanics trying to fit the wrong tyres after mixing up the two rear wheels, leaving Massa stranded as his rivals streamed past.
That mishap ended Massa's hopes of earning any points in Shanghai as the 32-year-old emerged from the pits in last place.
"Unfortunately, another race that we lost important points," Massa, who eventually crossed the line a lap behind winner Lewis Hamilton in 15th place, told reporters.
"But what can I do? We need to understand everything that happens, when it's good when it's bad and try to make things better next (time)."
Rob Smedley, who joined Williams recently as their new head of vehicle performance, said the reason for the botched pitstop was clear and that the team needed to implement changes to prevent a repeat.
"What led to it was not having good enough procedures, not having good enough processes to catch things like that, to ensure things like that don't happen," Smedley, who was Massa's race engineer at Ferrari, said.
"We have to go away, be pragmatic, be very honest and open with each other inside the team, I think that's important. That's something I'm keen to do at Williams, to be absolutely transparent with everybody."
Williams had been tipped as potential title contenders after showing impressive pace in pre-season testing.
While their haul of 36 points after four races in 2014 is a marked improvement on the paltry five points they accumulated in the entire 2013 season, Williams have so far failed to deliver on that pre-season promise.
"First race somebody pushed me out, I lost massive points," Massa said referring to the Australian Grand Prix when Caterham's Kamui Kobayashi ran into the back of his Williams.
"Last race I was fighting for third, fourth and after the safety car I finished seventh so lost points. And this race another problem that made me lose points.
"So for sure I'm frustrated for what's happened in so many races. I hope we don't see that anymore and I hope we can have consistent races from now on."
(Editing by Pritha Sarkar)