Vestegaard took a heavy touch in defence and then attempted to prevent Jamie Vardy from running through on goal by making a lunging tackle on the edge of his penalty area.
The Danish international, who was the last Southampton defender in the situation, appeared to win the ball cleanly although his follow-through collided with Vardy’s ankle.
Referee Robert Jones adjudged the challenge to be worthy of a red card, and following a review from the VAR, Jon Moss, the decision stood.
The dismissal was Vestergaard’s first in his 252-game career.
What has been said?
After the match, Hasenhuttl expressed his displeasure with the decision, saying: “The official explanation was denial of a clear goalscoring opportunity. The goalkeeper was near the ball, he could pick it up. I think he (Vardy) would never get this ball. This explanation is simply wrong.
“I thought it was (going to be) a penalty and then it would be even more difficult, but when you see the red card then you see that it was absolutely the wrong decision and we deserved to get something today.
“Jon Moss has seen it, the VAR, and he says it’s a red card, although Vardy never had the ball. The denial of a clear goalscoring opportunity is an argument that I cannot agree (with).
“I am not delighted with the red card decision but very delighted with the performance from my fighting side.”
What else happened in the game?
Following Vestergaard’s dismissal, Leicester saw plenty of the ball but struggled to penetrate Southampton despite their man advantage.
Hasenhuttl’s side managed to take the lead through a James Ward-Prowse penalty in the 61st minute, after Kelechi Iheanacho handled the ball in the area.
Jonny Evans equalised for Leicester shortly after, however, nodding in Iheanacho’s cross.
Despite dropping a league-high 23 points from winning positions this season, Southampton managed to hold on for a valuable draw that steers them further away from the relegation zone.
Where can I find out more?
For a closer look at the character Southampton demonstrated after going down to 10 men, Go Deeper with The Athletic‘s Dan Sheldon below.
(Photo: Neil Hall – Pool/Getty Images)