With tickets selling extremely well, a bumper crowd is expected to be in attendance as the Mariners aim to cut the gap at the top of the table to three points with a win.
Shields made it three victories in a row with a hard-fought 2-1 success at Warrington Town on Saturday and know the importance of picking up maximum points again.
They won the reverse fixture 1-0 in August with a Blair Adams goal, but will certainly not be taking Witton lightly having had a number of extremely competitive encounters with the Cheshire-based side over recent seasons.
The Mariners are second heading into the game, with Witton sitting second from bottom.
Phillips insists Shields will give full respect to their opponents, who triumphed 2-1 at 1st Cloud Arena in the 2019-20 season.
He knows that league positions will count for nothing.
Phillips said: "We can't and won't get complacent, because we know Witton will be highly motivated.
"My attention switched to this game immediately after our win on Saturday, because we have to be ready for the challenge they will pose.
"Every one of our games will be difficult because South Shields is a scalp, especially at our place.
"It's up to us to match them every step of the way and if we approach it correctly, we'll be a hard team to beat."
JJ Hooper is a doubt for the game after limping off in Saturday's game with a thigh injury.
Shields are hopeful Jordan Hunter will be back in contention for the first time since September as he readies himself for a return from a broken arm.
Kick-off at 1st Cloud Arena on Saturday is at 7.45pm, with the turnstiles set to open at 5.30pm.
Admission prices are £10 for adults, £8 for students, over-65s and disabled supporters, and £3 for under-16s, and tickets – including seats in the newly-improved CEFO Group Stand – can be purchased in advance until 3pm on matchday from Shields’ website. Cash turnstiles will also be in operation.