Match ends, Oxford United 0, Blackburn Rovers 3.
Blackburn made light work of third-round giantkillers Oxford to progress to the fifth round of the FA Cup.
League Two side Oxford had seen off Premier League outfit Swansea in the previous round, but conceded twice in the first half against the visitors.
Rovers took the lead through Ben Marshall's confident penalty after Simeon Jackson was brought down.
Debutant Tony Watt drilled in the second from inside the area, before Marshall curled in a free-kick.
Striker Jordan Rhodes was not selected as he is on the verge of a reported £9m move to Middlesbrough, but his replacement Watt made a decent start to his Rovers career by netting.
The closest Oxford came to scoring was when Liam Sercombe's angled drive was tipped around the post by goalkeeper Jason Steele.
Kemar Roofe, who scored twice against Swansea, dragged a shot wide as their FA Cup run came to an end.
Blackburn manager Paul Lambert: "Jordan Rhodes came and saw me, he wanted to go, and to be honest I thought the club should have taken the offer the summer before.
"He has been excellent for Blackburn, but the money is too good to turn down. The investment will help, the club has got to rebuild.
"I thought we were excellent. Oxford are a good side - they beat Swansea in the last round and they are doing well in their league.
Oxford manager Michael Appleton: "We knew it wouldn't be easy and we came across a really strong outfit in Blackburn.
"We weren't surprised by them - we knew what they are about. We played a part in all their goals, which is disappointing. We were a little bit naive and it probably shows why we are still a League Two side but we will learn from it.
"We are having a fantastic time this year, but we are where we are for a reason. We just came up a bit short today."
- 2BaldockBooked at 64minsSubstituted forKennyat 86'minutesBooked at 90mins
- 5MullinsBooked at 5mins
- 3SkarzSubstituted forEvansat 77'minutes
- 29BowerySubstituted forHyltonat 62'minutes
- 3SpurrBooked at 39mins
- 26LenihanBooked at 54minsSubstituted forTaylorat 71'minutes
- 32ConwayBooked at 79mins
- 35JacksonBooked at 50mins
- 8WattSubstituted forLawrenceat 61'minutes
- Andy Davies
- Shots on Target
Second Half ends, Oxford United 0, Blackburn Rovers 3.
Foul by Alexander MacDonald (Oxford United).
Craig Conway (Blackburn Rovers) wins a free kick in the defensive half.
Jonjoe Kenny (Oxford United) is shown the yellow card for a bad foul.
Foul by Jonjoe Kenny (Oxford United).
Craig Conway (Blackburn Rovers) wins a free kick on the right wing.
Danny Hylton (Oxford United) wins a free kick in the defensive half.
Foul by Chris Taylor (Blackburn Rovers).
Attempt saved. Craig Conway (Blackburn Rovers) right footed shot from outside the box is saved in the bottom right corner.
Foul by Kemar Roofe (Oxford United).
Thomas Spurr (Blackburn Rovers) wins a free kick on the right wing.
Substitution, Oxford United. Jonjoe Kenny replaces George Baldock.
Craig Conway (Blackburn Rovers) is shown the yellow card for a bad foul.
Alexander MacDonald (Oxford United) wins a free kick in the attacking half.
Foul by Craig Conway (Blackburn Rovers).
Corner, Blackburn Rovers. Conceded by Sam Slocombe.
Attempt saved. Simeon Jackson (Blackburn Rovers) right footed shot from the right side of the box is saved in the bottom right corner.
Substitution, Oxford United. Jordan Evans replaces Joe Skarz.
Goal! Oxford United 0, Blackburn Rovers 3. Ben Marshall (Blackburn Rovers) from a free kick with a right footed shot to the bottom left corner.