Boro have lost just one of their six league outings and enter this match one point better off than Cardiff, who are themselves unbeaten in three games.
However, Warnock has not won an away league match against City since April 2006 - a 1-0 victory as Sheffield United manager, drawing four and losing two since then.
Next month marks the one-year anniversary since Warnock departed the Cardiff City Stadium after a slow start to the 2019-20 season.
Experienced manager Warnock has plenty of happy memories from his time in South Wales, not least guiding the Bluebirds to the Premier League for just a second time.
The promotion expert has made clear that his aim is to take Boro back to the top flight, and he has made a decent start to his first full campaign at the Riverside Stadium.
Since narrowly losing to Watford on the opening day, Boro have drawn three and won two - those two victories coming in their last three matches, against Barnsley and Bristol City.
The Smoggies have kept a clean sheet in their last two matches and will be looking to keep their momentum going in the Welsh capital on Saturday.
However, Cardiff have produced some decent displays either side of the international break, even if that is not entirely reflected in their points return.
A goalless draw at free-scoring Blackburn Rovers and a battling 1-1 draw at home to Bournemouth sandwiched a 1-0 win at Preston North End, leaving Cardiff 13th.
The pressure is on Warnock's predecessor to match last term's top-six finish at the very least, though if that is going to happen then City need to improve their home form.
Harris's men are winless in their three home league games so far this season - they have not gone four without a win at home from the start of a Championship season since 2007-08.
This might be the perfect fixture to change that, though, as Cardiff have won their last four Championship meetings with Middlesbrough, conceding just one goal in those four games.
Cardiff City Championship form: LWLDWD
Middlesbrough Championship form: LDDWDW
Middlesbrough form (all competitions): LDDWDW
As for Boro, Warnock revealed after the win over Bristol City on Tuesday that captain Britt Assombalonga remains a fitness doubt due to a fresh injury issue.
This is the second of five games in a fortnight for Middlesbrough, so Warnock may be tempted to rotate in other areas of the pitch.
Cardiff City possible starting lineup:
Smithies; Bacuna, Morrison, Nelson, Bagan; Ralls, Vaulks; Murphy, Wilson, Hoilett; Moore
Middlesbrough possible starting lineup:
Bettinelli; Dijksteel, Fry, McNair; Howson; Spence, Morsy, Saville, Johnson; Roberts; Akpom
We say: Cardiff City 1-0 Middlesbrough
This will be an emotional occasion for Warnock on his first return to the Cardiff City Stadium since departing the Bluebirds 11 months ago.
His new side have made themselves very tough to beat - the true hallmark of a Warnock side - but they do not tend to do well in this fixture.
Cardiff have won 15 of their last 19 home league games with Boro, including victories in each of the last three by the same 1-0 scoreline, which we can see being repeated here.