This was the Argentinian player's second win of the day in what is his third appearance at the UTS. He had ousted "La Monf" Gael Monfils 3-0 prior to this clash at the Süwag Energie Arena, giving him a perfect day at the tournament.
The UTS differs from events on the ATP Tour in many ways, with the format more like a game show than a tournament in some aspects. The players battle it out across quarters, with the first to three quarters winning the match. There are also no games at the UTS - instead, players build up a running score and serve two points apiece, with the one who has the most points at the end winning the quarter.
Schwartzman dominates majority of match
"El Peque" (which is an abbreviation of "pequeño", meaning "shorty") started out strong at the Showdown, winning the first two quarters 14-10, 16-13. However, World No. 6 Rublev fought back hard in the third quarter, winning 16 out of 23 points in a bid to turn the match around. For a time, it looked as though he was succeeding in doing so, as he won the third quarter 16-7 to force a decider.
However, the event also has the added advantage of UTS cards. Each player starts the quarter with two of these - one which can make their winners count for three points and one which forces their opponent to serve and volley. The "steal serve" card also allows players to serve four times in a row.
It was in the fourth quarter that Schwartzman opted to use his three-point UTS card to help him build up a 15-8 lead. Although Rublev fought back again to get to 13-15, it was not enough to defeat the 31-year-old.
Schwartzman: every win is important for me
Speaking after the match, Schwartzman admitted that it had been a difficult year and he was glad to be winning matches now.
"I lost a quarter but even in that one I felt great, so it was a very good day for me," he said, "This year was not the best. These kinds of wins are important for me – every win right now is very important for me."