Ex-Blues and Spurs defender feels this could be a pivotal time in the race for Champions League places and Roberto Di Matteo\'s men could make up ground.Former Tottenham Hotspur and Chelsea defender Jason Cundy believes Spurs face their most difficult game of the Premier League run-in at Sunderland and insists the Blues must capitalise on any slip-ups by their rivals.Cundy is predicting the sternest of tests for Tottenham at the Stadium of Light on Saturday lunchtime before Chelsea take on Wigan at Stamford Bridge and Arsenal host Manchester City on Sunday.“Sunderland will be tough opponents for Spurs,” Cundy told Goal.com. “You have just got to see where they are in the table – tucked in just behind Liverpool – to see that.“If you ask any Sunderland fan if they had a chance of finishing above Liverpool when Steve Bruce was sacked they would have laughed at you.“But Sunderland are now a very good side as they showed in that 3-3 draw at Manchester City. Martin O’Neill is getting the best out of his players as he has done throughout his managerial career.“Stephane Sessegnon is a constant threat and I like the boy James McClean on the left-hand side as well plus Nicklas Bendtner seems to be scoring goals again. He has a wonderful goal against City and one the week before so they have got goals in them.“This will be a very difficult game for Spurs – far tougher than it would have been under Steve Bruce because this is a very different Sunderland side.”Cundy feels Chelsea must intensify the pressure on their fellow contenders for a top-four spot as a tough run-in looms for Roberto Di Matteo’s Champions League semi-finalists.