Miami, FL (Sports Network) - Tim Duncan can smell a fifth championship ring.
Duncan, the linchpin in the Spurs' previous four title runs, is playing near perfect basketball in a potential closeout Game 6 at American Airlines Arena.
The future Hall-of-Famer has missed just two of his 13 attempts in a monster 25-point first half to guide San Antonio to a 50-44 lead over the defending champion Miami Heat.
Duncan also pulled down eight rebounds and scored seven points on an 11-0 flurry to end the half, stunning a home crowd looking to see the Heat force a deciding Game 7.
Kawhi Leonard has totaled 10 points and five rebounds to make up for Manu Ginobili being held scoreless thus far. Tony Parker is also being held in check with just four points on 2-of-6 shooting.
Mario Chalmers has woken from a three-game slumber and poured in a team-high 14 points for the Heat, who trail despite hitting 5-of-10 from behind the arc.
LeBron James has logged nine points and five assists as he tries to avoid falling to 1-3 in his Finals career. Dwyane Wade and Chris Bosh each have a quiet six points so far.
After the Spurs pulled out a tight series opener, the teams have traded blowout victories despite being close games at halftime. San Antonio rolled to a 10-point win Sunday to take a 3-2 series lead and is looking to hand Miami consecutive losses for the first time since January.
A fast-paced start was highlighted by Leonard's dunk over Mike Miller in transition, a throw-down that was half stiff-arm, half tomahawk slam.
There were five ties and four lead changes in the opening quarter, the last coming when Chalmers capped his 10-point frame with his second 3-pointer of the night to give the Heat a 27-24 lead in the final minute.
Chalmers, who shot 4-for-19 from the floor in the three games in San Antonio, gave the Heat their biggest lead at 40-33 early in the second quarter.
That's when Duncan, who made his first eight shots, took over. He went on a personal 6-0 run to pull the Spurs within one, then rattled in a turnaround jumper in the lane to tie things at 44-44 with under two minutes left in the half.
After feeding Duncan for a dunk, Boris Diaw put in two himself on a layup before Leonard's tip-in just before the buzzer suddenly gave the Spurs their biggest lead.
San Antonio has made 53 3-pointers in the series to surpass the previous mark of 52 set by the Celtics in the 2008 championship round.
Danny Green pushed his personal Finals 3-point record to 26 with one make thus far in Game 6.