Aftet three hours, 16 minutes, it was the 21-year old American who came through with a 7-5, 3-6, 4-6, 6-4, 8-6 victory to reach the third round of a major for the first time in his career and a match with 15th seed Milos Raonic.
Opelka claims career-defining win to reach third round of a Slam for the first time
The match went as was expected in the first set as both players were dominant on serve. Through nine games, the server won 36 of 40 points, Wawrinka able to match Opelka hold for hold to move ahead 5-4, neither man sniffing a break point.
Opelka won his first career title earlier this year at the New York Open on indoor hard courts and the American had the first two break chances of the contest at 5-5, 15-40. After wasting the first opportunity, he took the second and proceeded to serve out the set to 15.
The American is improving his all-around game and his volleys are becoming a weapon on the grass, the second game of the second set as evidenced by a lovely winner to level at 1-1. He was under pressure for the first time all match in the fourth game.
At 30-40, Opelka fired a 137mph ace to save the first break chance, but a netted forehand on a second opportunity gave Wawrinka a 3-1 lead. The Swiss bypassed an opportunity for a double break edge at 4-1 ahead, a game after saving three break chances.
Opelka was in trouble again at 5-2 down, falling behind 15-30, but he was able to rescue the deficit and hold, putting the pressure squarely back on Wawrinka. The three-time major champion fell behind 0-30, but responded by winning the final four points to square the match at one set all.
The American came out blazing to start the third set with successive service winners, but was soon in a 0-40 hole in the third game. After saving all three chances, the last with a deft, deep volley, Wawrinka boldly took the fourth with a trademark backhand winner.
The Swiss was the one more convincing on serve this set, having won the last 13 points while pressuring the Opelka serve in nearly every game. A huge serve by Wawrinka gave him a two sets to one lead and the 22nd seed seemed to be well and truly in control now.
The early stages of the fourth set were key for Opelka's chances as he saved three break points over his first teo service games. The set seemed to be poised for a tiebreak as each man settled into a rhythm until the 21-year old seized his chance in the tenth game to break and force a deciding set.
In the early stages of the fifth set, each player had early break point opportunities, Opelka with two in the second game, Wawrinka with one in the third game, but neither man could break through. The closest brush with a break was at deuce on the American's serve at 5-5, but he won the last two points to hang on.
The three-time major champion gave Opelka a dose of his own medicine with an ace to close out a love hold to knot the set at 6-6 and carved out a break point, but the American forced an error with a big serve on his way to a hold for a 7-6 edge.
Serving to stay in the match for a third time, Wawrinka netted a forehand on the first point and faced two match points. Opelka showed some good defense with a backhand to force a final unforced error as the 22nd seed again fired into the net to end a terrific contest.