Jankovic then continued her trademark baseline mix of placement, consistency and selected power
to take full advantage of Williamsí apparent injuries as the American wore white tape wrapped above and
below her right elbow as well as around her left thigh.
Serving leading 3-1 30-15 in set two, Jankovic struck an ace down the tee before Williams netted a crosscourt forehand on the following point to trail 1-4.
The American steadied her groundstrokes to take the next four games to lead 5-4.
However after an oncourt visit from her coach as well as visible, vocal anger, Jankovic mixed in more slices and topspin groundstrokes which drew several errors from Williams as Jankovic retook the lead 6-5.
Serving to stay in the match, Williams committed three groundstroke errors to face the first of three match points.
The American struck a crosscourt backhand volley winner to save match point one before Jankovic would send two return of serves long to lose match point two and three.
Then at deuce and seemingly feeling physically better, Williams struck a backhand down the line winner which she followed up with a 102 miles per hour serve and a crosscourt forehand winner to reach the tiebreaker.
In the tiebreaker, Williams committed four forehand errors to trail 2-4 before striking several powerful forehands as well as backhands which forced errors from Jankovic to level the match at one set all.
With Williams now consistently delivering considerably more powerful serves and groundstrokes than earlier in the day and with Jankovic still visibly upset at her inability to close out the match in set two, the American quickly took a 4-0 set three lead.
The two competitors then exchanged breaks of serves before Williams served for the match at 5-1.
Jankovic netted three groundstrokes before Williams struck a surprise ace out wide, her only ace of the day, to end the match.
Williams who routinely held serve at love in set three had only won eight points total in set one.
Monday in round three at Indian Wells, Williams takes on the unseeded Lucie Safarova of the Czech Republic.
Safarova, a former top five player has won the last two matches versus Williams. However the duo have not met since 2015.