Nel got married on Saturday evening an hour after the close of the second day in the fourth Test at Centurion with the West Indies.
But major celebrations were put on ice as Nel returned to the cricket ground for the third day's play on Sunday.
The dedication paid off when he had Lara caught behind for 34 in the first innings and then trapped him leg before for six when West Indies were forced to follow on.
Nel, 26, said: "Getting married is a special feeling, a bit like getting your first five wickets in an innings. But getting Brian Lara out twice in a day is also a special feeling."
Nel has dismissed master batsman Lara five times in the West Indian's eight innings in the series in which South Africa already hold an unbeatable 2-0 lead.
"I'm really determined to get him out each time I bowl to him," said Nel, now a firm fixture in the South African attack.
The paceman queried West Indies' commitment after the tourists struggled again in the face the home side's daunting 604 for six declared.
"Sometimes I don't know if they show enough pride to play for their country," said Nel, who took three for 64 from 18 overs in the first innings.
"They can be a bit too relaxed and they don't seem to have the pride and deep-down desire that we have."
The West Indies followed on 303 behind and reached 44 for two when bad light ended play seven overs early. They need another 259 to make South Africa bat again.
Nel's wedding arrangements were all made and venues booked 10 months ago when he was on the periphery of the squad.
