Novak Djokovic showed his class during his intense three-set battle with Canada’s Denis Shapovalov after coming to help a crowd member in distress.
The World No.2 battled past Shapovalov in an emotion-charged encounter to book Serbia's place in the ATP Cup semi-finals.
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The atmosphere was so intense chair umpire Carlos Bernardes was forced into intervene and speak to the fans at one stage as the over-excited crowd interrupted games.
But Djokovic over came the distractions and carved out a tense 4-6 6-1 7-6 (7-4) comeback win on Friday.
However, the Serbian showed his class when he was serving for the match.
At 0-30 down, a spectator fell ill and briefly delayed proceedings.
However, Djokovic immediately offered the female fan a bottle of water as the crowd attended to the woman.
Djokovic was praised after remaining classy in such a high-octane and intense match.
Novak Djokovic gives bottle of water to the person in the crowd that's feeling bad. Yep, that's Novak who you criticise so much.— Novak The Champ🏆 (@SanjaSkipy) January 10, 2020
Touching scene on Ken Rosewall Arena as Djokovic tosses a bottle of water to a fan in distress.— The Truth Commission (@DemandTheTruth_) January 10, 2020
Djokovic bringing them water. Classy move.— Owen (@tennisnation) January 10, 2020
The world No.2's stirring win followed Dusan Lajovic's 6-4 6-2 rout of Felix Auger-Aliassime and propelled Serbia into a semi-final on Saturday against Russia.
But it was anything but routine for Djokovic amid wild scenes inside Ken Rosewall Arena.
Crowd tensions boil
Tensions boiled over midway through the second set when Shapovalov received a code violation for allegedly telling a Serbian heckler to "f*** you".
Chair umpire Carlos Bernardes called Canadian captain Adriano Fuorivia over to order him to calm Shapovalov down as he struggled to control the boisterous, mostly pro-Serbian crowd.
After dropping six straight games to concede the second set, Shapovalov did well to regain his composure and pile the pressure on Djokovic in the decider.
Feeling the heat, Djokovic remonstrated with Bernardes after receiving a warning himself for an audible obscenity in the sixth game of the set.
Despite the umpire demanding unruly fans behave or go home, Djokovic further fuelled emotions when he urged the crowd to fire up even more after he held for 3-3.
He then sent Serbian supporters into a frenzy when he broke Shapovalov three games later, only to drop serve while serving for the match.
Vanquished but gracious, Shapovalov warmly embraced Djokovic at the net after finally succumbing after two hours and 40 gripping minutes.
"Brisbane had some amazing support but this was a different level," Djokovic said before thanking his legion of Serbian fans in his native tongue.
In a rare double treat for Sydney fans, world No.1 Rafael Nadal will be in action on Friday night when he leads Spain into quarter-final battle with Belgium.
A tasty semi-final encounter with Australia on Saturday night looms large for Spain if the Davis Cup champions can continue on their merry way.
Nadal will be a warm favourite to down David Goffin in their top-seed encounter while Roberto Bautista Agut will be just as short odds against Steve Darcis.