Southampton made it a happy return to St Mary’s, as the two Armstrongs scored second-half goals to help secure victory over AS Monaco.
The Ligue 1 side, who finished third last season to qualify for the Champions League, edged in front six minutes before half time through a smart finish from Alexander Golovin, assisted by former Saint Takumi Minamino.
Having been restricted to shots from outside the box throughout the first period, Saints drew level seven minutes after the interval when Adam Armstrong pounced on Mohamed Elyounoussi’s parried shot to score his second goal of pre-season.
Cue the usual raft of substitutions, but it did not halt Saints’ momentum, as Stuart Armstrong found the net within three minutes of coming on, turning sharply in the box and finishing precisely.
It was left to the skipper to give the team’s first victory of pre-season the seal of approval, as Armstrong’s fellow substitute James Ward-Prowse guiding a perfectly-placed shot into the bottom corner from 20 yards.
For the first time in pre-season, the manager reverted to his preferred 4-2-2-2 formation, with French pair Yan Valery and Romain Perraud in the full-back positions.
Perraud was making his first appearance of the summer having recovered from an injury that has disrupted his preparations for the Premier League campaign, which gets under way next week.
Only Kylian Mbappé outscored Monaco captain Wissam Ben Yedder in Ligue 1 last season, and it would take a last-ditch block from Lyanco to thwart the danger man early on.
Saints soon began to get into their stride. Ché Adams’s attempted forward pass to strike partner Adam Armstrong rolled back to him invitingly, only for Adams to scuff his shot wide from 20 yards.
Long-range shooting would become a common theme for Saints, as Armstrong dragged one wide and Elyounoussi stung the palms of Alexander Nübel.
But it was a former Saint who was next to threaten, as Minamino turned sharply in the box and drew a fine save from the flying figure of Alex McCarthy, who may have been helped out by the frame of his goal in keeping Monaco at bay.
Armstrong was next to test Nübel after combining with Nathan Redmond, before Adams had another go that was deflected behind, as Saints racked up the shot count from outside the penalty area.
The hosts were the team in the ascendancy but the speed at which Monaco counter is impressive.
Minamino left Lyanco on the seat of his pants before Golovin found Ben Yedder, who shimmied away from a couple of challenges but lost his balance completely just as he wanted to pull the trigger, much to the amusement of the locals.
But the Saints fans were not laughing when Minamino dribbled into the area and was only half-tackled, resulting in the loose ball being dispatched low inside the near post by Golovin from 12 yards.
There was still time in the first half for Ben Yedder to arrow a volley back across McCarthy’s goal and wide.
Perraud’s comeback would last 45 minutes, replaced at the interval by Moussa Djenepo, but the rest of the starters would be given at least another 20 minutes to impress.
Having been restricted to shots from distance, Saints got their equaliser from much closer range, with Armstrong the architect and the finisher all by himself after some excellent persistence from Redmond to win the ball inside the final third.
Armstrong’s good work in scuttling into the box created the chance, initially for Elyounoussi who was only denied by a spectacular diving save from Nübel, but the striker was quickest to react and sharp off the mark to prod home the rebound.
Elyounoussi was hungry to get in on the act himself, curling a shot inches wide soon after the goal, before strong claims for a penalty were dismissed as he jinked into the box.
The substitutions that followed gave Saints fans a first glimpse of Joe Aribo along with familiar stalwarts Ward-Prowse, Kyle Walker-Peters and Stuart Armstrong, who continued the upward trajectory of the team’s performance.
Aribo’s languid style and ability to glide past defenders quickly created a chance as his low cross fizzed along the six-yard box, before his precise square pass picked out substitute Armstrong, who assessed his options, spun and planted an inch-perfect finish into the top corner from virtually on the penalty spot.
Another home debut followed, for Armel Bella-Kotchap, before Ward-Prowse finished a sweeping team move in style, as Saints flooded forward in the same vein as Monaco in the first half.
Still full of running with 90 minutes under his belt, Ibrahima Diallo fed Walker-Peters on the right, whose enticing square pass was brilliantly dispatched by Ward-Prowse on the run, low and curling away from Nübel to finish an impressive night’s work.