By Martyn Herman

LONDON (Reuters) - Towering Croatian Ivo Karlovic, once pigeonholed as a serving machine with few other buttons to press, showed there is more to his game than aces at Wimbledon on Monday.

The 37-year-old, one of a growing number of 30-somethings in the men's draw, served 26 untouchable deliveries to dispatch teenager and compatriot Borna Coric 7-6(8) 7-6(7) 6-4.

But the second oldest man in the draw demonstrated that he is not just a one-trick pony.

His volleying was McEnroe-esque at times and his unsung groundstrokes, especially a grass-hugging slice, were rock solid when the 19-year-old Coric dragged him into baseline rallies.

Karlovic's movement too belied that of a man who at 2.11 metres loomed large on the tight confines of Court Eight, drawing gasps from spectators who had never seen him close up.

Even when he was in trouble, trailing 2-6 in the second set tiebreaker, the priceless commodity of experience came to his rescue.

He slammed down an ace, another serve winner, and produced a couple of textbook volleys as he surged back to snatch a decisive two-set lead.

"Only 26 today," Karlovic joked of his ace count that took his career total to a world record 10,851.

"Normally in three sets it's around 40. I must be under-achieving," added Karlovic, one of the 49 men aged 30 or over to start in the singles -- a Wimbledon record.

"I was in trouble in the second set but I was aggressive and went to the net and he was a little shaky. I was able to use the opportunity and after that I felt the match went my way."

Karlovic said it had been slightly weird to play a fellow Croat and, while he showed no mercy toward Coric, he had some encouraging words for the teenager.

"Of all the young players he is the best mentally," said Karlovic, who surprisingly for someone with such a service weapon has only made one quarter-final in 11 previous visits.

"Technically he is behind some of them but that's good because that's the easiest thing to work on. Mentally he is unbelievable."

For Coric it was another part of the learning process.

"He was one of the last guys I would have picked for a first round," he told Reuters. "But that's tennis. It was frustrating, I played okay, but he didn't give me much."

Having reached a career-high 33 in the world last year, Coric, one of several teenagers tipped for great things, is finding the next step tricky.

"These guys are not going to make it easy for us to come through. Even in their 30s they are fitter than ever and they also have vast experience of the Tour," he said. "Maybe it's gonna take a couple of years."

(Editing by Adrian Warner)