FULL-TIME REPORT: Oxford United 0 Blackburn Rovers 3

The sold-out Kassam Stadium clash threatened to be overshadowed by Jordan Rhodes’ impending departure to Championship rivals Middlesbrough.

But Rovers showed there is and has to be life without their top-scorer with an impressive and professional performance against their lower-league and giant-killing opponents.

Fit-again right-back Marshall opened the scoring from the penalty spot and rounded it off with a brilliant free kick.

Sandwiched in between was a terrific goal from the debutant who did much to take the match away from Michael Appleton’s men.

Watt was thrust straight into Rovers boss Paul Lambert’s side after the paperwork for his initial loan move from Charlton Athletic went through in time to play.

And he was joined in a much-changed starting line-up by fellow debutant Elliott Ward, who was assured throughout, and Simeon Jackson, who produced an excellent performance, full of pace, purpose and strength, on his first start for the club.

Jackson was swiftly into the action, pouncing on a loose ball and seeing his charge toward goal ended illegally by Johnny Mullins, who was lucky to escape with just a booking.

The U’s, managed by former Rovers boss Appleton, came into the fourth-round tie with confidence – and, according to the bookies’, as favourites, a fact that their fired-up opponents were aware of.

League Two high flyers Oxford had knocked Premier League Swansea City out of the last round and then claimed the scalp of League One Millwall to put one foot in the Johnstone’s Paint Trophy final.

But they threatened Rovers’ goal only once, in the 28th minute when Jason Steele got down low to his right to turn Liam Sercombe’s low drive around the post.

By that stage Steele’s opposite number, Sam Slocombe, had made a fine stop of his own to deny Ward from flicking in Craig Conway’s outswinging corner.

But the U’s goalkeeper could do nothing to prevent Marshall breaking the deadlock in the 36th minute.

Watt had been enduring a mixed start. He showed his class, however, when he turned sharply and played a pass through to his strike-partner.

Jackson was just about to pull the trigger when he was barged over in the box by boyhood Rovers fan Joe Skarz.

Marshall did the rest, planting his third successful penalty of the season past Slocombe, who went the right way yet stood no chance.

Watt had suddenly found his touch, leading and so nearly finishing a rapid breakaway as he exchanged passes with Elliott Bennett only to see his toe-poked effort turned over by Slocombe.

The former Celtic starlet was not to be denied, though, and in added time at the end of the opening period he won the ball midway through the Oxford half, advanced 10 yards before firing an inerring shot into the bottom corner.

Rovers wasted two golden chances to extend their lead after the restart.

Bennett unselfishly tried to pick out Watt when he should have had a go himself.

And then Tom Lawrence, who came on for Watt on what was his final appearance for the club before his loan ends, blazed the ball over the bar after a driving run into the area.

But Rovers did get the third goal their domination deserved in the 76th minute.

And what a goal it was too as Marshall curled a superb 20-yard free kick over the wall and into the corner of the net.

Jackson could and should have got the goal he deserved, seeing one fierce attempt turned behind by Slocombe, and another go begging, as he headed over a cross from the recalled Bennett.

But it was very much job done.

Oxford: Slocombe, Baldock (Kenny 86), Skarz (Evans 77), Roofe, Mullins, Wright, Sercombe, MacDonald, O’Dowda, Lundstram, Bowery (Hylton 62). Subs not used: Buchel, Ruffels, Ashby, Dunkley.

Booked: Mullins, Baldock, Kenny.

Rovers: Steele, Marshall, Ward, Hanley, Spurr, Bennett, Lenihan (Taylor 71), Evans, Conway, Jackson, Watt (Lawrence 61). Subs not used: Raya, Henley, Kilgallon, Duffy.

Booked: Spurr, Jackson, Lenihan, Conway.

Goals: Marshall 36pen, 76, Watt 45.

Referee: Andy Davies.

Attendance: 11,647 (1,485 away).