Michael Ballack [ Images ], who scored both goals in the 2-1 win over United on April 26 that opened up the championship, glanced in a header after an hour and fellow midfielder Florent Malouda [ Images ] made it safe late on.
United, 4-1 home winners over West Ham United on Saturday, and Chelsea both have 84 points but United have a goal difference advantage of 17. They visit Wigan Athletic next week and will retain the title if they at least match Chelsea's result against Bolton Wanderers at Stamford Bridge [ Images ].
"We know that we are always chasing after Manchester United," Chelsea manager Avram Grant [ Images ] told Sky Sports.
"They are a great team but we will give them a good battle and challenge until the end."
It was by no means plain sailing for Chelsea on Monday at a ground where they had not won in the league since 2001.
Chelsea looked short of invention throughout the half but took control after the break, with skipper Terry smacking a header against the bar as they camped in the home side's half.
The breakthrough came when Didier Drogba [ Images ] chipped in a free kick from the right and Ballack, who built his reputation in Germany [ Images ] as a regular scorer of important, late goals, rose six metres out to direct his header beyond keeper Steve Harper.
Chelsea then sat back and suffered some nervous moments as Nigerian forward Obafemi Martins and Owen both went close.
But the tension eased after 82 minutes when some slick passing ended with substitute Frank Lampard [ Images ] slipping a through-ball to Malouda, who slotted home calmly.
Grant had particular praise for Ballack, whom he described as "an intelligent player".
"I believe in intelligent football and that needs a player like him," said the Israeli. "He's in good form now, but all the team played well."
Terry said Grant had torn into the players at halftime and that they had responded in the second half with a "great professional job".
Looking ahead to next week's games, he added: "Wigan are on a great run, they came to the Bridge and put on a great performance and I think they will do the Premiership justice.
"We've still got a tough game against Bolton but if we pick up three points we've got a very good chance."