Carlos Alcaraz opened his Wimbledon title defence with a hard-fought victory over Estonian qualifier Mark Lajal.

The Spaniard won 7-6 (7-3) 7-5 6-2 to begin proceedings on Centre Court.

Alcaraz is attempting to win back-to-back major titles after triumphing at the French Open last month.

"Stepping on this court, it is the most beautiful court I have played on," said the 21-year-old. "I still get nerves when I play here.

"I practised for 45 minutes on Thursday and it was the first time I was nervous on practice because I was playing on this court."

Lajal, 21, battled hard on his first appearance in the main draw of a Grand Slam.

"Honestly it surprised me a little bit because I haven't seen him playing or practising too much," added Alcaraz.

"He has the level to go up a lot. He is really young, the same age as me, and I am sure I am going to see him more often."

Alcaraz will face Aleksandar Vukic in the second round after the Australian overcame Sebastian Ofner of Austria in a five-set thriller.

Meanwhile top seed Jannik Sinner found a way past German Yannick Hanfmann, winning 6-3 6-4 3-6 6-3 on Court One and played partly under the roof.

Hanfmann made life difficult for the world number one, but Sinner, who won the Australian Open in January, came through within three hours.

Sinner will now play compatriot Matteo Berrettini in the second round.

Qualifier Lajal frustrates defending champion Alcaraz

Following his deep run at Roland Garros, Alcaraz's preparations for this year's Wimbledon have been limited.

He played just two grass-court matches at Queen's where he suffered a surprise second-round defeat by Britain's Jack Draper.

The Spaniard looked somewhat rusty as Lajal, ranked 269th in the world, surprised the Centre Court crowd when he struck the first blow for a 3-2 lead.

Alcaraz was able to raise his level when it mattered, though, responding immediately with a break of his own before taking control of the tie-break to clinch the opening set.

His frustrations continued in the second set, with Lajal matching the reigning champion's energy with big hitting and crafty drop shots as the pair exchanged early breaks.

But the qualifier's confidence started to falter when Alcaraz broke to go 6-5 up before serving out the set.

There was no looking back for the three-time major winner, who raced through the third set and fired home a fierce forehand winner on his second match point.