Danny Guthrie insists Saints will not throw away their chance of a play-off spot.
The on-loan Liverpool midfielder has already seen Saints dip in form once since he arrived from Anfield in early March.
But recent results - both from Saints and from the other sides challenging for a top-six place - have meant Saints' run of one point out of 12 last month has not been as costly as first feared.
And having got themselves back into the top six, Guthrie believes Saints can stay there.
He said "Today against Sunderland will be a massive test for us.
"If we can beat them we will be right back in the thick of it.
"One of the reasons I came here was to play in big matches.
"The bigger the better for me - and they don't come much bigger than this at this level.
"There will be a big crowd, a great atmosphere and a good pitch - so it's all set up for a cracking game".
Full interview in today's Daily Echo.
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