Argyle's Rami Al Hajj is replaced by Michael Obafemi to huge applause from the Home Park faithful.

Image source, Rex Features

It was a deserved breakthrough for Cardiff, who have been the better side. As it stands they are heading out of the relegation zone - and Watford are heading for a fourth consecutive Championship defeat.

Darko Gyabi gets forward and decides to let fly with his left foot.

His shot is blocked but almost reaches Michael Baidoo in the box, however, United goalkeeper Jamie Cumming comes out to collect and keep the danger at bay.

Argyle's equaliser has definitely given them a lift as we go into the last 20 minutes.

Brent Pilnick
BBC Sport at Home Park

Image source, Rex Features

My colleague from the Plymouth Herald Chris Errington and I were just talking about Rami Al Hajj.

The conversations went along the lines of "When it's going well for him it's great, but when it's not - like tonight - maybe they need to change it".

At that very moment Al Hajj glanced in Tymo Puchacz's cross.....

What do we know eh?

A change by both sides as Cardiff's Chris Willock makes way for Ollie Tanner, while Edo Kayembe replaces Moussa Sissoko.

Dafydd Pritchard
BBC Sport Wales at Cardiff City Stadium

"He's one of our own," Cardiff fans sing as Cian Ashford further enhances his burgeoning reputation.

The 20-year-old academy product scored the winner as Cardiff won 1-0 at Sheffield United in the FA Cup on Thursday, and he's finished superbly again to net what could be a priceless goal in his team's battle to avoid relegation.

Double change for the visitors as Mark Harris and Przemyslaw Placheta are replaced by Dane Scarlett and Siriki Dembele.

Jerome Sale
BBC Radio Oxford commentator

It's a neat finish from Al Hajj.

Over the course of the hour it's probably a fair score, but in this half Oxford have looked more likely to score.

Ciaron Brown, who I just said had been faultless, receives a yellow card for a foul on Tymo Puchacz.

Typical curse of the commentator.

Dafydd Pritchard
BBC Sport Wales at Cardiff City Stadium

There's a bit more life in this game in the second half.

Tempers frayed earlier, with referee Oliver Langford lecturing players from both sides at a corner.

That bit of niggle has riled the Cardiff fans, and that's helping to lift what had been a flat atmosphere.

The first change and it's made by Watford boss Tom Cleverley, who brings on Rocco Vata for Ryan Porteous.

First, there is another opportunity for the visitors!

The ball is lifted into the box by Will Vaulks but there are no takers for United.

At the other end, Tymo Puchacz's excellent ball almost finds Morgan Whittaker who would have had a tap-in, but the ball is intercepted by Ciaron Brown, whose defending has been faultless so far.

That's got the Green Army going a little bit more though!

Brent Pilnick
BBC Sport at Home Park

Image source, Rex Features

It's been a pretty stale start to this second half, which is exactly what Oxford United will want.

The U's have had a couple of dangerous-looking long throws from Will Vaulks and troubled Argyle with some decent crosses.

You would imagine if Gary Rowett could call full-time on this game now he would - it would be a really important three points for Oxford and take them safely into mid-table.

Watford struggle to deal with a corner and, with keeper Jonathan Bond in no man's land, Francisco Sierralta heads off the line. Cardiff then attack again and Rubin Colwill shoots wide.

The visitors have undoubtedly reaped the benefits of the half-time break and Ciaron Brown's inviting centre somehow avoids Greg Leigh, when the left-back ought to have done better.

Oxford may have been fortunate to have been ahead at the break but they have come out the traps in the second half, and whatever Gary Rowett said, has definitely worked.

Katie Middleton
Ex-captain of Plymouth Ladies on BBC Radio Devon

It's been a similar sort of opening in this half as it was in the first half.

Argyle haven't settled and Oxford look comfortable at the moment in defending their lead. It might take something special to get an equaliser.

An excellent delivery from Oxford's Matt Phillips picks out first-half substitute Jordan Thorniley but the centre-back is unable to direct his header, which goes out for a goal-kick.

Cardiff have started the second half as they began the first - with plenty of possession in the Watford half. Hornets left-back Yasser Larouci, who has run hot and cold tonight, loses the ball near the edge of his own box, but his team-mates are back in numbers to cover.