His nerves almost got the better of him, but Lloyd Harris was elated to advance to the second round of the Madrid Open on Monday.
The South African tennis ace defeated 13th-seeded Grigor Dimitrov 6-3, 3-6, 7-6 (7/5) in a topsy-turvy contest.
"It was a big up and down match, [I led by] a set and a break, then [I was] a break up in the third too," Harris said afterwards. "I got a little bit nervous at the end, but I'm happy to close it out. I started to dictate again at the end."
The South African, currently ranked 54th in the world, was seemingly coasting when he led by a set and a break before a lower back injury curtailed his efforts.
But a medical timeout at the end of the second set appeared to work wonders as Harris surged to a 5-2 lead in the decider.
The match looked over when Harris had three match points up 40-0 on Dimitrov's serve but the Bulgarian somehow managed to escape.
Harris then lost serve while serving for the match but regained his composure in the tie-break.
There was another nervy moment when he missed two match points while leading 6-3 in the tie-break but a hard-fought point on serve sealed the deal.
It was only Harris' second ever win at Masters 1000 level, following on from his first round win at the Miami Open earlier this year where he cracked the ATP top 50 for the first time.
Harris next faces Australia's Alex de Minaur, who is ranked 24th in the world, in the second round on Tuesday evening.
In his only previous ATP Tour meeting with De Minaur, Harris prevailed 6-3, 6-7 (6/8), 7-6 (10/8) at the hardcourt event in Tokyo in 2019.
"He is a very tough opponent and he doesn't give you much," Harris told the ATP Tour website. "We had an epic match in the past."
Harris made headlines earlier in the year at the Dubai Championship where he reached his first final of an ATP 500-level event.
He lost to red-hot Russian Aslan Karatsev in the final but it was a successful tournament where he became the first qualifier in history to reach the championship match in Dubai.
En route to the final, Harris had knocked out top-seed and world No 4 Dominic Thiem, as well as Japan's Kei Nishikori, a former world No 4.
Harris is currently 10-6 on the season and 4-0 against top 20 opponents.