Four-time Madrid Open champion Rafael Nadal looked back to his best in the Spanish capital on Tuesday as he effortlessly took apart Andrey Kuznetsov 6-3 6-3.
The return to clay has seen Nadal - who was beaten in the final 12 months ago by Andy Murray - begin to shine again after troubles on the hard courts, and another record could beckon for the fifth seed.
Already in 2016 he has lifted the Monte Carlo Masters and Barcelona Open titles for a ninth time, and his convincing win over Kuznetsov suggests he could add to his Madrid record.
Things were not as simple for defending champion Murray as Radek Stepanek made him dig deep on his way to a hard-earned win.
Ultimately the Czech ran out of steam, and Murray was able to prevail 7-6 (7-3) 3-6 6-1 thanks to a dominant display in the decider, while Milos Raonic and Richard Gasquet are also through to the last 16.
LANDMARK WIN FOR DEL POTRO
It has been a long road back to full fitness for former US Open champion Del Potro following a wrist injury, but Tuesday saw the Argentine make a huge leap in his recovery.
Not since 2013 has Del Potro been competitive at an ATP 1000 tournament, but he showed glimpses of real quality in ousting 14th seed Dominic Thiem 7-6 (7-5) 6-3 in his opening match.
"I have just played my best match since I came back to tennis after my surgeries," an emotional Del Potro said. "I've had a great test against a very high-level player."
MONFILS BATTLES THROUGH, DIMITROV OUT
Gael Monfils - playing with his ankle heavily strapped - and Roberto Bautista-Agut both came through their final first-round ties, but last year's quarter-finalist Grigor Dimitrov was an early casualty - the Bulgarian losing to Spanish wild card Pablo Carreno-Busta in straight sets.
ACES NOT ENOUGH FOR KARLOVIC
Big-serving Ivo Karlovic would have hoped to have taken his second round place after firing down 30 aces against Denis Kudla, but the Croatian found himself beaten in three tie-breaks.
Having taken the opening set, Karlovic was unable to finish the job and after wasting two match points in the final game he was knocked out by the 23-year-old Kudla after two hours, 33 minutes on court.
TOMIC FAILS TO CONTEST MATCH-POINT
Australia's Bernard Tomic is also out, albeit in controversial fashion after the world number 22 opted not to try and return on match-point against Fabio Fognini - Tomic beaten 6-2 6-4.