Since arriving at St Mary's in the summer from Bundesliga club Borussia Monchengladbach, the 26-year-old defender has found himself in and out of the Saints' first-team picture.
Vestergaard played the full 90 minutes in six of his first seven Premier League games, missing only the 2-1 loss to Everton in August, but was then dropped to the bench for seven of the following eight league matches.
With Ralph Hasenhuttl replacing Mark Hughes in December, the 6ft 5in defender is now featuring more prominently as he completed 90 minutes in five of his last six league games, according to Transfermarkt.
Prior to his appointment at St Mary's, the Austrian had spent his entire managerial career in Germany and managed both Ingolstadt 04 and RB Leipzig in the Bundesliga, while Vestergaard played for Hoffenheim and Werder Bremen in the country.
As a result, both individuals found themselves on opposing sides from time to time, and speaking to the Daily Echo, the Denmark international outlined exactly what defines Hasenhuttl's teams and how he hopes to be part of a similar transition to his philosophy.
“I played against his teams but didn’t know him personally,” said Vestergaard. “His teams were uncomfortable to play against and aggressive. They press up high and don’t give you much time on the ball. I’m looking forward to us becoming uncomfortable like I know his teams can be.”