Saints slipped to their first pre-season defeat as two second half defensive errors saw them beaten 2-0 by Schalke in Austria.
The game was a massive step up in opposition for Mauricio Pochettino’s men, whose previous two summer matches had been against Spanish minnows.
Schalke finished fourth in last season’s Bundesliga and boast a striker that has moved for combined transfer fees of more than £50m over his career in the shape of Klass-Jan Huntelaar.
For all that though it was Saints that were marginally the better team in a first half of few chances.
Kelvin Davis in the Saints goal only had one save to make, and that was also routine from Michel Bastos.
Both teams made three changes at the break, and that included the introduction of Huntelaar.
It changed the game almost immediately.
Suddenly Schalke looked far more threatening, and the Saints defence under a lot more pressure.
Kelvin Davis had to save a Huntelaar header five minutes after the restart but there was no let off on 58 minutes as the Dutch striker gave his side the lead.
Jose Fonte was caught out and Christian Clemens got in behind the Saints backline.
Davis did well to save his initial effort but there was nothing that he could do to stop Huntelaar forcing home the rebound.
Lambert had a rare Saints chance in the second half but uncharacteristically turned Adam Lallana’s good ball in over the bar from close range.
Some more lacklustre defending from Saints was punished on 69 minutes as Schalke scored a second and wrapped up the win.
They failed to clear a high cross from the right and Saints were made to pay the price as Joel Matip lashed in a half volley.
The game was still a useful exercise with both Dejan Lovren and Puncheon playing the full 90 minutes.
Saints now have two clear days before taking on Besitkas at the same ground.
Saints: K Davis (Gazzaniga 64), Chambers (Clyne 64), Lovren, Hooiveld (Fonte 45), Shaw (Fox 64), S Davis (Schneiderlin 45), Wanyama (Cork 64), Isgrove (Lallana 45), Puncheon, Rodriguez (Ward-Prowse 64), Lambert (Mayuka 64).
Schalke: Hildebrand, Uchida, Ayhan (Matip 45), Höwedes (Hoogland 62), Fuchs, Goretzka, Jones (Neustadter 74), Barnetta (Clemens 45), Draxler (Huntelaar 45), Bastos (Meyer 62), Szalai (Pukki 62).