United host Arsenal on Sunday with Champions League football for next season all-but wrapped up, but both sides find themselves some way adrift of title winners Chelsea - with the Blues cantering to the top-flight crown and currently in possession of an 11-point lead at the summit.
Louis Van Gaal’s side are currently 16 points off the pace set by Jose Mourinho’s men, while the Gunners are two points better off with have a game in hand, so are likely to finish slightly closer to the runaway leaders.
Both Arsenal and United are expected to improve again this summer and challenge for the title in 2015/16, but Stam believes that Van Gaal and Arsene Wenged need to improve defensively if their respective sides are to wrestle the title away from Stamford Bridge next season.
"Maybe they need to defend a bit better,” he said.
“Chelsea not playing most attacking of football but they get results. You need that as a team."
Stam, who was highly successful in his time at Old Trafford - making 125 appearances for the Red Devils during a three-year spell - refused to criticise Mourinho for his side’s style of play this season.
The Blues started the season on fire and were arguably the league’s most entertaining side, but a 5-3 defeat to capital rivals Tottenham Hotspur on New Year's Day saw them become more defensively-minded and start to grind out results.
That saw many labeling the eventual Premier League champions as 'boring', but Stam is not among those dissenting voices.
"Every manager has their open way of playing. Mourinho's chosen this style and they get results,” he added.
"Good for the team and the players. If they defend a bit better, you will get results and win the league as well."