The two sides do battle on Sunday evening with Boro looking to take a giant step towards an immediate return back to the third tier following relegation last season against a Southend side that only missed out on automatic promotion on the final day.
And Westley predicts two thrilling ties in a bid to reach Wembley.
“Play-off semi-finals are brilliant games. High-octane, high-pressure situations, they are not for the faint-hearted,” Westley told the Hertfordshire Mercury.
“I’m sure there will be full houses in both grounds for both occasions. The real positive from our point of view is that we will take a really strong travelling support away for the second leg as well as there being a packed house for the first game.”
“Southend are a very good side and they’ll be a very tough nut to crack. We had a 4-4 aggregate over the two games.
“They are a very good side, make no bones about it.”
A shock 3-1 loss to Morecambe last Saturday saw Phil Brown’s Southend slip from third to fifth and they will be hurting ahead of a trip to Broadhall Way, a ground where they lost 4-2 back in February.
But Brown says they must pick themselves up if they are to bounce back.
“We had our sponsors’ evening the other night and I couldn’t believe it because everyone in the room was at a real low ebb and that shouldn’t be the case at all,” he told Echo News.
“I had to grab hold of the microphone to lift the mood and get people going again because it’s a very good season we’ve had.
“I know we’re all human and we’re hurting from losing at Morecambe but I remember being at the same do at the same time of last season and everyone was really buoyant, bouncing off the walls.”
Brown will check on Jerome Binnom-Williams (ankle) and Myles Weston (calf) ahead of kick off while Jake Cassidy, who had been unwell, is also fully fit and available for action.
Stevenage are certain to make changes having rested plenty of players on the final day. The likes of Dean Wells, Bira Dembele, Jerome Okimo, Dean Parrett, Tom Pett and Chris Beardsley are all set to start.