John Mensah is tipping Sunderland teammate Sulley Muntari to make a big impact.
The more games Muntari plays for Sunderland the more his fitness will improve and Mensah believes fans are yet to see the best of their on-loan ace from Inter Milan.
"We all know Sulley played for Portsmouth and did well - helping them to win the FA Cup," he told the Sunderland Echo.
"Then he went to Inter and did well as well and has scored goals for the national team. It was Sunderland's decision to bring him here, but they asked my opinion.
"He's a great player and he's starting to demonstrate that at Sunderland.
"When Sulley came, he didn't have a lot of fitness. But he played against Stoke and then played for the national team last week.
"He's going to still make a few mistakes because he's not played many games. But I believe he'll still show his quality while he is here."
