Fulham skipper Danny Murphy knows better than most the threat Sunderland's Darren Bent poses at Craven Cottage on Sunday.
The midfielder is familiar with Bent from his time at Charlton, where the striker made a name for himself during the 2006 season after moving from Ipswich Town.
Murphy left The Valley halfway through that campaign to join Tottenham, a move Bent completed himself in 2007.
The striker left Spurs to join Sunderland in the summer and has hit the ground running in the North East - scoring nine Premier League goals this season.
"If you switch off once with Darren, he'll kill you," Murphy said. "He's a big factor in why Sunderland are where they are in the league.
"I've played with Darren and I'm a big fan of his because the one thing he always does is get goals. You might not see him for 80 minutes in a game but he'll keep running, he'll keep working hard to get his chances, and he'll put one away.
"Sunderland also play with that Steve Bruce tenacity that was evident at Birmingham and Wigan. They've got a great work ethic and I'm expecting a difficult game."
Bent's impressive goal tally has helped Sunderland reach a healthy position in the top half of the table and that is not something that surprises Murphy.
"There has to be some so-called surprise packages in the top half because there aren't enough top-four teams to go around," he said.
"There are still six places to fill in the top 10 and some of those will be so-called surprised packages.
"I would have thought at the moment, with the investment made at the start of the season and the quality of the players they brought, I don't think too many of us will be surprised to see them in the top half of the table. That is where they will be aiming for."