A late surge from Leeds Rhinos helped them secure a 32-16 win against St Helens in the Super League Grand final at Old Trafford.
The Rhinos were ahead at the break through Man of the Match Rob Burrow, who burst clear of the Saints defence to score the first try of the contest, with Sinfield securing the extras.
St Helens got themselves level soon after the restart when Tom Makinson touched down, courtesy of the video referee, before Foster successfully kicked the conversion.
In a fluctuating match, Saints found themselves 12-8 ahead when Michael Shenton scored the third try of the evening, before another Foster penalty edged them 16-8 in front.
However, four tries in the final 20 minutes for Leeds turned the game around and earned them their fifth Super League title.
St Helens then lost captain Paul Wellens with a suspected broken arm, as Leeds continued to run riot.