For weeks, Sam Allardyce was a broken record as his press conferences essentially boiled down to "clean sheet, clean sheet, clean sheet".
It was the big bug-bear of the Sunderland boss, who has built a career and a reputation on teams who have been difficult to break down, rather than the defensive soft touch which the Black Cats have been for so much of this season.
The streak without a shut-out was an appalling 16 games before the stalemate against West Brom earlier this month.
But over the last two months - particularly since the Lamine Kone and Younes Kaboul partnership has come together - Sunderland have looked far more resilient, with three clean sheets in the last four games keeping the points tally ticking over.
Plenty of pundits have understandably tipped Jermain Defoe as Sunderland's difference-maker in the survival battle and they could well be proved right. Certainly, Newcastle and Norwich would both love a finisher of the 33-year-old's calibre.
Yet at present, Sunderland's back-line is also looking more resilient than either of their two relegation fight peers.
The loss of £8.5million centre-half Timm Klose is a huge blow for Norwich, while despite their rally over the last eight days, Newcastle's defence still remains vulnerable.
Sunderland required a couple of excellent saves from Arsenal old boy Vito Mannone to register a stalemate against the Gunners, but again, Allardyce's swide were tough to break down.
Centre-halves Kone and Kaboul were again excellent - the latter rescuing Mannone when he came charging out of his goal for a header, only to completely fluff his attempted clearance.
Their calmness, power and organisation is spreading too.
DeAndre Yedlin's crossing lets him down when he gets into the final third, yet the on-loan Spurs right-back's defending is improving all the time - no mean feat when up against a genuinely top class prospect such as Alex Iwobi.
If Sunderland had nicked a winner at the other end, then it really would have gone down as a stunning defensive effort from Allardyce's side.
However, a point is a healthy return for Sunderland. After all, with Arsenal still battling to secure their top four spot, this was probably the Black Cats' toughest test during the run-in.