(CNN) -- Ryan Giggs and Park Ji-sung scored in each half as Manchester United won 2-0 at Middlesbrough on Saturday to go six points clear at the top of the English Premier League.
Ryan Giggs points the way to victory after scoring the opener at the Riverside.
The defeat leaves Boro deep in relegation trouble and with just three games left to avoid the drop.
By contrast, United have one hand on the Premiership trophy for the third year in a row and owed victory to a captain's performance from the evergreen Giggs on his 801st appearance for the Red Devils.
Their nearest title rivals Liverpool can cut the gap to three points with victory over Middlesbrough's north-east neighbors and fellow relegation strugglers Newcastle on Sunday.
But United will have a game in hand going into the closing games of the season and with the benefit of a near fully-fit squad.
Alex Ferguson could afford to rest the likes of Cristiano Ronaldo, Edwin van der Sar and Michael Carrick ahead of Tuesday's Champions League semifinal decider against Arsenal.
But he was still able to include Wayne Rooney, Giigs, Paul Scholes, Nemanja Vidic and Dimitar Berbatov in his starting line up at the Riverside.
Ferguson told Sky Sports: "It's a big step forward. "I just keep saying that if you whittle the games away, eventually there are no games left, and hopefully we will still be at the top of the table when we get to that point.
"It was a very good performance. They all worked their socks off and once we got a hold of the ball, we always looked a danger."
After a scrappy opening, Giggs made the breakthrough as Federico Macheda, making his first league start for the club, stepped over Vidic's ball across the edge of the penalty area to leave the Welshman to beat Brad Jones.
Scholes missed a pair of chances to put United further ahead before half-time, but the second half was only six minutes old when Rooney's clever reverse pass played in Park to score decisively.
Boro tried to rally, but were largely outclassed and substitute Carlos Tevez and Rooney might have added a third.
Defender John O'Shea also went close to his second goal of the week having scored the only goal in the home leg against Arsenal, but was denied by good defending by Matthew Bates.
In other Premier League action on Saturday, Chelsea moved level on points with Liverpool in third place after a 3-1 win over Fulham in the west London derby.
Nicolas Anelka, Florent Malouda and Didier Drogba scored Chelsea's goals ahead of their Champions League home tie against Barcelona.
Arsenal were also in good form ahead of their semifinal clash with Manchester United with a 3-0 win at Portsmouth.
Jermaine Jenas scored the only goal of the game as Tottenham Hotspur beat West Bromwich Albion 1-0 to leave the visitors on the brink of relegation.
Robinho scored as Manchester City beat Blackburn 3-1 to keep up their bid for a Europa league place, while West Ham won 1-0 at Stoke. Wigan and Bolton were goalless.